DIY 3d printed negative scan box. Comments please ...

A while ago I joined a local "Technology Cooperative" and I've been taking some classes there on 3d printing.

A couple of years ago I saw the Film Toaster at Photo Plus, and it looked like a workable idea, although for $1300 us it's quite steep. I was thinking that something much simpler could be made that would be nearly as functional for much less.

Now that I think I've graduated from doing simple 3d print things like little kitchen gadgets and Baby Yoda dolls, I've been playing around with a design for a box to do just this.

I'm envisioning a box to hold a light source and a two-part plate with a 36x25.. (for a slight overscan) which would all sit on a more or less standard copy stand.

Simple! Almost minimalist.

I haven't printed any of this yet, and I'm interested in hearing if anyone here sees any issues that I'm overlooking.

The one issue I'm well aware of is that (at least the pieces that touch the film) will need to be carefully sanded and polished, as 3d prints tend to be rough, particularly around the edges.

I still haven't figured out what kind of light source to try. (LEDs???) Any suggestions?

Thanks.

General feedback:

1. Make film mask interchangeable so that multiple film sizes and formats can be scanned with it by simply replacing the mask part.
2. Make the box large enough to comfortably house the largest film format you plan to support scanning
3. Make the box with some channels to put diffusion material between the light source and the film, you may need more than one layer of diffusion to get a smooth output
4. Make the box deep enough so that there is enough distance between the diffusion and film that the diffusion material will be out of focus when scanning at reasonable apertures.
5. If possible, put in some facility to have standoffs for adjustable feet so that the whole assembly can be leveled with the camera. This could take the form of some blocks on the bottom that can be drilled and threaded so that the feet can be screwed in/out to adjust the level at each corner of the box.

Mask specific feedback:

1. The area where the hole is for the film should be as thin as possible and/or the edges angled away from the opening at least 45 degrees, if you don't do that, you'll get shadows and/or reflections in the scan from the thick material surrounding the film

Light specific feedback:

1. Ideally, use a light source with as high of a CRI as possible
2. Be prepared to make it as bright as possible, you ideally want to scan with an ISO of 100, a shutter speed of at least 1/60, and an aperture of at least f/4.0, this requires a lot more light than many realize. Less light means higher ISO (more noise), longer shutter times (more noise, and vibration induced reduction of sharpness), and more open aperture (way shallower depth of field, more difficult to keep the whole frame in focus).

I personally use a strobe in my setup, but if you can get it bright enough with enough diffusion, LEDS can also work. Halogen/Tungsten can also work, but will have heat management issues. I'd avoid fluorescent lights, as it can make it difficult to use higher shutter speeds with some cameras as the flicker can show up as banding, depending on the camera and shutter speed.

Let me know if you have any other questions, I've scanned a lot of film and will be happy to pass on any general knowledge I've acquired through doing so.

Cura has "ironing" function which you should for the surface to reduce scratching of negative.

dmr said:

A while ago I joined a local "Technology Cooperative" and I've been taking some classes there on 3d printing.

I still haven't figured out what kind of light source to try. (LEDs???) Any suggestions?

Click to expand...

As Adrian mentioned, the spectrum (CRI is a proxy for this) of your light source is important if you plan to scan color film. (It's much less important for black-and-white, obviously). No LED light that I'm aware of has a true continuous visible light spectrum, but the very high CRI LED lights might be good enough for any practical purposes. LEDs are probably the most convenient light source you could use. Most fluorescents have poor spectrums. Tungsten and halogen lights, as well as electronic flashes, have good continuous spectrums (and consequently CRIs of 100). But all three have convenience drawbacks of various kinds. A bit of a bummer.

I also like Adrian's suggestion of adjustable height feet. Getting the camera square to the film that you're scanning is a necessary part of camera scanning, and some people will benefit from the ability to adjust the film platform rather than the camera platform. It's clear to me that camera scanning can produce really top-notch results, but many advocates of it downplay these two issues—i.e. using a quality light source and aligning the sensor with the target film. They aren't trivial.

A much bigger complication that you can think about (but not necessarily tackle in v1 of your box) is how to facilitate multi-shot scans, which is important mainly to people who shoot medium and large format film. This is the main thing that keeps me from junking my scanner. I can get demonstrably better scans of my 6x6 and 6x7 negatives using my camera scan setup, but only if I shoot the negative at high magnification, in sections, and then stitch them together. I need 3 or more shots (with my 24-megapixel digital camera) to meaningfully improve on what my dedicated scanner can do, with the films I use. It's a hassle, and I haven't seen a good DIY/inexpensive solution yet.

Adrian Bacon said:

General feedback:

3. Make the box with some channels to put diffusion material between the light source and the film, you may need more than one layer of diffusion to get a smooth output

Click to expand...

Adrian, I was just thinking about the issue of diffusion today, and wondering if certain diffusion materials would affect the spectrum of the light source. (A simple color cast would not be a problem.) Do you have any thoughts on that?

I guess my first instinct for a quick and dirty solve would be to cannibalize the diffusion sheet from something like an old Logan light box made specifically for viewing slides. I'd guess that Logan would choose a suitable diffusion material. I wouldn't necessarily trust the translucent sheet from a cheap LED panel.

villagephotog said:

As Adrian mentioned, the spectrum (CRI is a proxy for this) of your light source is important if you plan to scan color film. (It's much less important for black-and-white, obviously). No LED light that I'm aware of has a true continuous visible light spectrum, but the very high CRI LED lights might be good enough for any practical purposes. LEDs are probably the most convenient light source you could use. Most fluorescents have poor spectrums. Tungsten and halogen lights, as well as electronic flashes, have good continuous spectrums (and consequently CRIs of 100). But all three have convenience drawbacks of various kinds. A bit of a bummer.

I also like Adrian's suggestion of adjustable height feet. Getting the camera square to the film that you're scanning is a necessary part of camera scanning, and some people will benefit from the ability to adjust the film platform rather than the camera platform. It's clear to me that camera scanning can produce really top-notch results, but many advocates of it downplay these two issues—i.e. using a quality light source and aligning the sensor with the target film. They aren't trivial.

A much bigger complication that you can think about (but not necessarily tackle in v1 of your box) is how to facilitate multi-shot scans, which is important mainly to people who shoot medium and large format film. This is the main thing that keeps me from junking my scanner. I can get demonstrably better scans of my 6x6 and 6x7 negatives using my camera scan setup, but only if I shoot the negative at high magnification, in sections, and then stitch them together. I need 3 or more shots (with my 24-megapixel digital camera) to meaningfully improve on what my dedicated scanner can do, with the films I use. It's a hassle, and I haven't seen a good DIY/inexpensive solution yet.



Adrian, I was just thinking about the issue of diffusion today, and wondering if certain diffusion materials would affect the spectrum of the light source. (A simple color cast would not be a problem.) Do you have any thoughts on that?

I guess my first instinct for a quick and dirty solve would be to cannibalize the diffusion sheet from something like an old Logan light box made specifically for viewing slides. I'd guess that Logan would choose a suitable diffusion material. I wouldn't necessarily trust the translucent sheet from a cheap LED panel.

Click to expand...

It depends on what you're using... If you're using actual diffusion material from somebody who makes it like Rosco or Lee, then it should be relatively neutral, though will still tend to introduce a slight Kelvin shift. If you're re-using a material like copy paper, beware. Things like optical brighteners will mess with you. In my experience, to get a truly smooth and diffuse light source, I've found that it's generally better to have multiple thin layers. What I've done in the past is make a frame out of foam core board that fits inside my light source with as large of a hole in the middle of the frame as possible, then put thin sheet diffusion (like a Rosco R100 Supergel) on both sides. This gives about a quarter inch between each sheet. If it's still got hot spots or needs to be smoothed out more, then put another foamcore frame on top and another layer of diffusion material on top of that. Wash, rinse, repeat until you get the desired amount of uniformity. Usually by 3-4 layers it's pretty uniform, but does suck up light. I'd avoid using one single thick piece of diffusion because it's rarely enough unless you also do a lot of light engineering behind it to make the light hitting it as uniform as possible, but if you're going to do that, then why bother with the diffusion? It's far easier to just stack thin diffusion with the only real downside being that it takes light.

I'm getting a lot of mixed reviews (and mixed thoughts) regarding the spectra of the various light sources.

Yes, I agree that the spectra of various LED sources are discontinuous and not smooth at all.

However, all of the recent photo trade shows I've been to have had TONS of professional grade studio lights and on-camera lights based on LEDs and, of course, intended for color.

Honestly, I'm confused on this!

If possible, put in some facility to have standoffs for adjustable feet so that the whole assembly can be leveled with the camera. This could take the form of some blocks on the bottom that can be drilled and threaded so that the feet can be screwed in/out to adjust the level at each corner of the box.

The area where the hole is for the film should be as thin as possible and/or the edges angled away from the opening at least 45 degrees, if you don't do that, you'll get shadows and/or reflections in the scan from the thick material surrounding the film

Click to expand...

Keeping in mind that I'm going for simplicity and minimalism here, as in I don't want the "perfect" to stand in the way of the "good", I've been thinking of using those small stick-on feet on the bottom of the box, mostly for stability when sitting on the copy stand. Realistically, the error from level should be in the small fraction of a millimeter. LOL, the terms "drill" and "thread" are things I'm trying to avoid here.

I do see the point of a bevel in the top of the box, and that's very easy to add.

Cura has "ironing" function which you should for the surface to reduce scratching of negative.

Click to expand...

Thanks. Cura is what we are using for the slicing and printing and I'll look for that.

My LED light source - a Nanguang CN-T96 - is much brighter than the typical "tracing pad" and is advertised as having a fairly high CRI (says "CRI>90" and also, "CRI: Ra: 95"). The Nanguang CN-T96 is also cheap if ordered on eBay from a Chinese source ($40, USD). The downside is, each of the 96 LEDs forms a distinct hot spot, so significant diffusion is required.


I used two layers of "DuraLar Matte" which I got at an art supply store - one on either side of a pane of glass which is positioned about 1/2" above the LED light. I like Adian's idea of using something thicker than glass to seperate the two layers.



With the 2 layers of diffusion material, and at f/11 and ISO 200 (the base ISO for my digital camera), most of my exposures are around 1/60 sec, depending on the density of the negative/slide. I put two layers of matt board on top of the glass, and I use a negative/slide holder from my film scanner (not shown) so my film is raised above the diffusion material by about 1/4"

The reason you want to be able to level the top of the box is because your tabletop / floor may not be level. The easist way to align the plane of the film with the plane of the sensor is to use a bullseye bubble level. I just use pasteboard shims under whichever corner of my box is too low until the bubble is centered. This is somewhat fussy, and too easly knocked out of alignment, so adjustable feet would definitely be an improvement.
EDIT: I see you are using a copy stand; probably easier to level that, and not worry adjustable feet on the lght box.

Don't forget to consider: all lights are going to produce a certain amount of heat, some much more than others.

dmr said:

I'm getting a lot of mixed reviews (and mixed thoughts) regarding the spectra of the various light sources.

Yes, I agree that the spectra of various LED sources are discontinuous and not smooth at all.

However, all of the recent photo trade shows I've been to have had TONS of professional grade studio lights and on-camera lights based on LEDs and, of course, intended for color.

Honestly, I'm confused on this!



Keeping in mind that I'm going for simplicity and minimalism here, as in I don't want the "perfect" to stand in the way of the "good", I've been thinking of using those small stick-on feet on the bottom of the box, mostly for stability when sitting on the copy stand. Realistically, the error from level should be in the small fraction of a millimeter. LOL, the terms "drill" and "thread" are things I'm trying to avoid here.

I do see the point of a bevel in the top of the box, and that's very easy to add.



Thanks. Cura is what we are using for the slicing and printing and I'll look for that.

Click to expand...

I totally understand your desire for simplicity, however, the points I brought up are key for having a functional system. If you’re Ok with having part of the scanned frame potentially out of focus because it’s not aligned with the sensor and whatever copy stand/tripod you’re using doesn’t have the facility to adjust (many don’t unless you spend good money), then that’s totally your decision. If it were me, I’d at least build in standoffs, even if I never put in adjustable feet (by drilling/threading) so if I found that I needed it, I wouldn’t have to make another box, but again, that’s just me. It’s your design and totally up to you.

with regards to light source, again, full spectrum/high CRI is best, but other light sources can be made to work. With the lights intended for color video work, they are designed to work by reflecting off of what is being recorded, as opposed to being transmitted through what is being recorded. Color negative film is essentially a very complex color filter, and so using a light source with very narrow bands of spectra can result in undesirable/difficult to correct visual color artifacts in the output.

runswithsizzers said:

I like Adian's idea of using something thicker than glass to seperate the two layers.

Click to expand...

yep, I’ve found that more distance between each layer of diffusion produces much more smoothing effect per layer as the light has more room to spread/bounce around before hitting the next diffusion layer. After trying a number of different methods in my own setup, I settled on foam core as the separator for ease of working with the material and it’s reasonably thick enough and is easy to get cheaply.

the matte duralar can work, but can have patterns in it that can be visible, so if using that, it’s really important to make sure it’s really out of focus.

Adrian, thank you for sharing your insights! Do you mind sharing picture of your setup with the flesh as light source? I'm using Nikon bellows unit with negative/slide holder, Rosco LED and only for BW negatives. I would like to try using it with strobes (Nikon's SB series) but all my ideas are fairly clumsy. This picture is from a few years back.

gorbas said:

Adrian, thank you for sharing your insights! Do you mind sharing picture of your setup with the flesh as light source? I'm using Nikon bellows unit with negative/slide holder, Rosco LED and only for BW negatives. I would like to try using it with strobes (Nikon's SB series) but all my ideas are fairly clumsy. This picture is from a few years back.
View attachment 240685

Click to expand...

next time I’m at the lab I’ll snap a few photos of just the light source, but will be not including the full setup as there are a number of things I have in development that might actually be marketable products. The light source itself isn’t actually that interesting. It’s just a speed light firing into a heavily modified light panel. I have all the diffusion and baffling on the inside of the panel, so from the outside, there’s actually not much to see, and I’d very much rather not take it apart to show the innards as it’s heavily used on a daily basis and I don’t want anything to change. The speed light I’m using is a Lumopro LP180. I picked it because it’s manual, and has a high voltage port so I can power it from a wall adapter, and it has a wired sync port, so I can trigger it from the camera with a trigger cable. I’ve burned through 2 LP180s and am currently on my third one (yes they do wear out and fail with use), unfortunately, it looks like Lumopro won’t be making them any more so I’m on the hunt for a replacement and will make a new light source designed around whatever strobe I end up with. I’ve also completely blasted through (and then a whole lot more) the designed shutter count of the camera I was previously using, which prompted replacing it with the camera I’m currently using, the Canon 90D.

Thank you in advance Adrian!
I'm looking for "elegant" DSLR scan solution with little volume and super small footprint. So far I'm happy with bellows system for 35 and will make similar for 6x6.
I did experiment with just one SB28 but it was very hard to get even lighting. 3 small LED "bulb modules" had enough light output for framing and focusing.

Thanks everyone

runswithsizzers said:

My LED light source - a Nanguang CN-T96 - is much brighter than the typical "tracing pad" and is advertised as having a fairly high CRI (says "CRI>90" and also, "CRI: Ra: 95").

Click to expand...

Thanks Runz! Things like this are what I'm looking for, as in examples of what people before me have done along this line, whether or not done with a 3d printer or more "low tech" tools.

I googled that light source, and even though it's about three times the area of the box size I want, it shows me that a LED light source can and will work with such a project.

Various "maker" sites have LED strips, banks, squares, etc. which are physically smaller. I like the idea of LEDs for illumination for simplicity and lack of heat, and if photographers are comfortable using them to render skin tones, and others have used them for scanning, I'm feeling more at ease with using them for this project.

Someone else on "another network" posted the link to a quite different 3d printed one, using an external light table ...

https://www.thingiverse.com/thing:3985120

Adrian Bacon said:

I totally understand your desire for simplicity, however, the points I brought up are key for having a functional system. If you’re Ok with having part of the scanned frame potentially out of focus because it’s not aligned with the sensor and whatever copy stand/tripod you’re using doesn’t have the facility to adjust

Click to expand...

Okay, everyone, please check my math here. ... Using the formula for Depth Of Field obtained from that Ultimate Authority on Everything, Wikipedia DOF ~= 2u**2 Nc / f**2 where u = distance to subject, N = the f-number, f = focal length of the lens, and c is the (quite appropriately named) circle of confusion.

Let's assume a 1:1 90mm copy lens, 90mm away from the image, shot at f/4. I'm a bit confused (pun intended) about the COC, but the typical numbers I'm seeing for it for 35mm photography are around .2mm-ish.

Solving for DOF we get 8100 * 2 * 4 *.2 / 8100 or 1.6mm and, intuitively, unless things are very sloppy, there should be no "out of square" errors approaching that. If we assume the worst, we stop down to f/8 and get ...

8100 * 2 * 8 * .2 / 8100 or 3.2mm, far exceeding any tolerances in build or alignment.

Any obvious errors in my math or logic here?

Along the same line, keeping a relatively large distance between the film plane and the light source, particularly with some diffusing material, keeps that light source well out of the depth of field and should result in very clean and consistent illumination.

gorbas said:

I'm looking for "elegant" DSLR scan solution with little volume and super small footprint.

Click to expand...

That is exactly what I'm going for here!

Thanks again, gang!

Are you going to use a full-frame digital camera to copy 35mm film in one shot? That is, will you be shooting at 1:1 magnification or something else?

Your depth-of-field caculations may very well be correct, but I am not smart enough to follow you. I used different depth-of-field calculations and got different numbers.

The online calculator I used is based on magnification. Go to <this link> and scroll down to the "Macro Depth of Field Calculator"
If I enter "1" for the magnification, "Full frame" for the Sensor Size, and select f/4 for the aperture, the DoF is calculated as "0.34mm" - that is tight! Even at f/11 that calculator is showing only 1.41mm DoF at 1:1 magnification.

I use a 1.5 crop sensor camera, so I'm working at lower magnification (about 0.65x). My "eyeball" tests convinced me I was starting to see softer images due to difraction becoming objectionable at f/16, so I usually shoot at f/8-f/11.

dmr said:

Thanks everyone



Thanks Runz! Things like this are what I'm looking for, as in examples of what people before me have done along this line, whether or not done with a 3d printer or more "low tech" tools.

I googled that light source, and even though it's about three times the area of the box size I want, it shows me that a LED light source can and will work with such a project.

Various "maker" sites have LED strips, banks, squares, etc. which are physically smaller. I like the idea of LEDs for illumination for simplicity and lack of heat, and if photographers are comfortable using them to render skin tones, and others have used them for scanning, I'm feeling more at ease with using them for this project.

Someone else on "another network" posted the link to a quite different 3d printed one, using an external light table ...

https://www.thingiverse.com/thing:3985120



Okay, everyone, please check my math here. ... Using the formula for Depth Of Field obtained from that Ultimate Authority on Everything, Wikipedia DOF ~= 2u**2 Nc / f**2 where u = distance to subject, N = the f-number, f = focal length of the lens, and c is the (quite appropriately named) circle of confusion.

Let's assume a 1:1 90mm copy lens, 90mm away from the image, shot at f/4. I'm a bit confused (pun intended) about the COC, but the typical numbers I'm seeing for it for 35mm photography are around .2mm-ish.

Solving for DOF we get 8100 * 2 * 4 *.2 / 8100 or 1.6mm and, intuitively, unless things are very sloppy, there should be no "out of square" errors approaching that. If we assume the worst, we stop down to f/8 and get ...

8100 * 2 * 8 * .2 / 8100 or 3.2mm, far exceeding any tolerances in build or alignment.

Any obvious errors in my math or logic here?

Along the same line, keeping a relatively large distance between the film plane and the light source, particularly with some diffusing material, keeps that light source well out of the depth of field and should result in very clean and consistent illumination.



That is exactly what I'm going for here!

Thanks again, gang!

Click to expand...

the circle of confusion affects your DOF, and what resolution the camera is will affect the circle of confusion size. Canon cameras embed the circle of confusion in the raw metadata they produce for a given camera and lens, so it’s easy to figure out what your DOF will be, then you can simply plug it in here: http://www.dofmaster.com/dofjs.html, which will tell you what your DOF is. I’ve found that often times, your usable DOF is smaller than you realize in practice, and it’s difficult to make very fine alignment adjustments to a camera on the end of a copy stand arm. It’s a lot easier to have threaded feet with relatively fine thread on the film carrier for alignment, but again, that’s just me relaying my experience. If you want to go a different path, that’s totally up to you.

I made a slight tweak to the item that holds the film and faces the light, as shown in the first image below. This view is the side opposite the one shown in the view above, and shows the bevel to control any shadow cast on the negative.

The second view below shows an item I stumbled on last night on one of the "maker" supply sites. It's the light source for a small LCD display, without the LCD display part, and it's ridiculously cheap.

Does anyone see any reason why it would not work as a light source, just placed in the bottom of the box? It looks like it should not need any diffuser at all.

The URL for the item (I have not ordered it yet) is here: https://www.adafruit.com/product/1621 in case anyone wants to look at it.

The third image below shows one of many inexpensive LED things out there. There are tons of them available, from single "stick-on" LEDs to strips to arrays to some that even let you control the color, as in values for R, G and B separately. I was thinking of using one or more LED arrays until I found the flat source in the second view.

What I do not like for this product: so even though there is only one single white LED, it provides near-uniform lighting.
Nice thing, It's crazy cheap!
I'm using similar uniform LED light source from ROSCO company, a few years old. Quality of light spectrum is simply horrible, shame for the company with such reputation for colour fidelity products and as it is, I can use it just for BW. It was very expensive back in the day.

dmr said:

I made a slight tweak to the item that holds the film and faces the light, as shown in the first image below. This view is the side opposite the one shown in the view above, and shows the bevel to control any shadow cast on the negative.

The second view below shows an item I stumbled on last night on one of the "maker" supply sites. It's the light source for a small LCD display, without the LCD display part, and it's ridiculously cheap.

Does anyone see any reason why it would not work as a light source, just placed in the bottom of the box? It looks like it should not need any diffuser at all.

The URL for the item (I have not ordered it yet) is here: https://www.adafruit.com/product/1621 in case anyone wants to look at it.

The third image below shows one of many inexpensive LED things out there. There are tons of them available, from single "stick-on" LEDs to strips to arrays to some that even let you control the color, as in values for R, G and B separately. I was thinking of using one or more LED arrays until I found the flat source in the second view.

Click to expand...

the second image looks pretty nifty, though I’d have to wonder how bright it is.

Listen to Adrian WRT CRI.
If you ever plan on scanning colour film, bright smooth spectrum light is imperative.
See all the people talking about difficulties with reversing C41? It would be much easier with a flash backlight.
Flashes are cheap and plentiful. You don’t need fancy features, just a guide number north of 30 1m ISO 100.

True, you need a constant backlight for focus. That could be a LED or a halogen light.
With a good CRI light, you won’t have to turn it off every shot, though. So halogen is what I use.
The flash “deafens” most of it out anyway.

Screws for adjusting the holder is also not optional.
It will always be far easier to adjust the holder than the camera.
Same with ability to move the holder.
It will come in real handy to be able to slide the holder smoothly around in level, to make stitch scanning.
Acrylic coaster feet on glass could be the ticket.

I have one linear guide waiting for scanning purposes. They are quite cheap, for example https://www.ebay.com/itm/Linear-Gui...hash=item2f329357be:m:mCQgek2vrJA-giYlW9KNdOg

vedostuu said:

I have one linear guide waiting for scanning purposes. They are quite cheap, for example https://www.ebay.com/itm/Linear-Gui...hash=item2f329357be:m:mCQgek2vrJA-giYlW9KNdOg

Click to expand...

Thanks.

I've been thinking (yes, dangerous, I know) and I'm toying with the idea of making this a horizontal thing instead of vertical and something like that would definitely work, although my idea would have a movable camera plate with an oblong block sliding in a slit in the platform.

I don't have a copy stand, and the better ones are several hundred and take up all kinds of room. My original idea for the light box came from the fact that I don't have a light table and the better ones cost and take up all kinds of room, so I'm kind of mentally regrouping thinking of designs that don't need anything else, well, except for the camera and macro lens that is.

One modification I was playing with the other day was to expand the box part (below), add a base for stability, and do a groove into which an extension for a camera mound would be slid, but I ended up running into the limit on the length of what the Taz-5 (the printer I have access to with the largest bed) can do.

For those who care (and for those who don't) I've successfully 3d-printed what is basically the first version of the scan box and it does look promising.



I painted the inside of the box and the top of the middle item flat white. In 20/20 hindsight, they did have some white 3d print filament, and I guess I could have used that instead of the default grey color. I placed the backlight thing (not really sure of the best name to call it) in the bottom of the box, not permanently mounted yet. Not having a real power supply for it yet, I took it in and got it to work (with some help, of course) in the lab using an adjustable bench power supply. Using a 150 ohm resistor (that's what one of the guys who knows these things said was a good value to start with) it starts to light at about 4 volts and anything over 10 volts gives it no significant change in brightness. The light intensity looks very consistent across the plane.



The whole thing fits together like a glove! I'm impressed! {blow on fingernails, wipe on blouse} The top two pieces which hold the film fit together very precisely. I centered the one image and slid on the top.

I have not sanded or smoothed it, so I was VERY careful in loading a test slide, one from a roll of Ektachrome 100 that I shot last year.



The light appears to be bright white and consistent across the film plane. I have no practical way (that I know of) to measure the color spectrum, so further tests with this light source will probably be trial and error.



I do not have anything close to a good copy lens! For this "proof of concept" I zoomed way out and used manual focus and manual exposure. It's still a very significant crop. I got as close as I could still being able to manually focus on the film. For some reason, auto-focus appeared to always want to focus on the (very dimly lit, lab lights were out) top of the box. Auto exposure grossly overexposed things, with the majority of the frame being the dark top of the box.

This was hand-held. I tried to look as straight down on the lab bench as I could and hold it as steady as I could in that contorted position. Trial and error seemed to give 1/125 and f/11 as the best exposure.

Anyway, here's the first "scanned" image.



Yes, far from perfect, but it looks promising! I have NO CLUE what the shadow in the upper right is. I do not remember seeing it in the viewfinder. It may be from one of the connecting wires, which were simply placed in so they would fit. As you see, there's some obvious barrel distortion in there.

For comparison, the same image, scanned last year on the KM SD IV, is below.

Next steps are to semi-permanently mount the light source, get a dedicated power supply set up (I know I have a whole drawer full of various charger plugs of uncertain origin), and then get a good copy lens and copy stand. Unless something unexpected happens, I don't think I'll have to re-3d-print anything.

Of course I'll need to carefully evaluate the color situation.

Thanks for the feedback, gang!

Now? Does anyone have any suggestions for a good but not extortive macro/copy lens for the X mount?

dmr said:

The whole thing fits together like a glove! I'm impressed! {blow on fingernails, wipe on blouse}

Click to expand...

Excellent, keep going!

Very nice! keep at it. iterative revision wins the day in these instances. I didn't build the rig I use today in one fell swoop. It is a continual and ongoing iterative thing.

For those who care, I did a quick non-scientific test to do a sanity check on the purity of the light coming from the backlight module that I used in the last test.

These were both shot with the Fuji that I intend to use to copy the negatives and slides. One of these was in outdoor daylight. The other was in the bathroom, vanity and overhead lights off, illuminated by the light from the backlight module in the box.

Anyone care to guess which is which?