Anti-glare material UK

[Bobby Brewster]

Hi all,

I'm new to scanning using a DSLR to scan. I have problems keeping negatives eg Tri-x and any 6 x 6 flat. My cheapo set up won't do it so I'm looking for some glass or plastic to cover the negative and hold it flat to the light source which is pretty even. Does this approach seem sound?

If so, I wonder if anyone has any suggestions for anti-glare material that might do the trick and also any suppliers in the UK? I have seen mention online of using non-reflective plastic with some success and this seems like a budget, though delicate, option which I'd like to try. I'm not sure where to get it though.

Thank you

 

[_T_]

Many glass suppliers carry acid etched glass. I would call around to local glass shops and ask if they carry it.

You would want it etched on one side only.

 

[Bobby Brewster]

Many glass suppliers carry acid etched glass. I would call around to local glass shops and ask if they carry it.

You would want it etched on one side only.

I'm a bit confused. Is acid - etched not translucent ? Surely this would be really not good for scanning or have I misunderstood what you meant? I don't want to use it to diffuse light but to put on top of the negative so I can keep it flat while using my camera to take a picture of it.

 

[_T_]

The anti glare properties of the glass are not of very great importance. The light source is on the opposite side of the glass so it won’t produce reflections. You might need to turn off the room lights though as those might interfere.

But the problem you will inevitably find when using glass to hold your film flat is that the interface between the glass and film isn’t perfect and the slight differences in distance between the film and glass will produce newton rings which will ruin your scan.

To keep the newton rings from forming you will need to use anti-newton-ring glass or anr glass. This is also called acid etched glass. The acid etched surface would contact the smooth side of the film and the emulsion side usually can be held down with regular glass.

If you are dead set on buying anti reflective glass you would want to go to a framing shop and ask them to order you a piece of museum glass. Museum glass has a coating which reduces reflections but is generally not very useful for scanning film.

 

[250swb]

In the UK you can buy pre-cut pieces of high quality ANR glass from Knight Optical. You definitely don't want to confuse ANR with anti reflective museum glass, they are worlds apart while even though they seem like they should be similar, for one thing ANR glass is much heavier, better for keeping things flat, and has a more refined surface.

https://www.knightoptical.com/

 

[koraks]

Is acid - etched not translucent ?

Don't confuse 'translucent' with 'transparent'. Glass that's frosted, ground or etched is virtually always still translucent - i.e. it passes much of the light that hits it. But it's not necessarily (generally not) transparent in the sense that the light is being diffused. You don't want diffusion in your application, evidently.

anti-newton-ring glass or anr glass. This is also called acid etched glass

Is it? IDK what the usual method of producing AN glass is; I can very well imagine it's etched. However, regular etched glass has a distinct matte appearance, doesn't it? Not just any kind of etched glass will do in this application. I understand that some have had decent results using the glass from anti-glare image frames, but others claim that the surface texture is a problem. I really don't know; I've only ever worked with regular AN glass (no rings) and with plain glass (problems with newton rings).

 

[_T_]

The glass etching process produces an effect where certain areas of the micro surface are etched at different rates causing the whole surface to become irregular and sort of wavy on a very small scale. I don't know if all ANR glass is produced this way but it is possible to use certain types of what is called acid etched glass for film scanning.

You may find that there are visible artifacts due to the texture of the glass, but this is also possible with glass marketed as ANR glass. The surface texture is necessary to produce the ANR effect.

There are sometimes other products falsely sold under the name of acid etched glass which are simply glass coated with textured plastic, or frosted glass but that is an entirely different product and won't work for scanning.

 

[Bobby Brewster]

Yes I wouldn't want translucent which is why I was afraid the acid-etched would exhibit such a quality. Obviously I know little about the whole acid-etching area. I notice that Knight optical have the product I thought I meant at the start of this thread and on their site the smallest they sell is 50cm x 50cm so I will need to call them and ask about smaller sizes.

Thank you and I will try and get some of this in the size I need.

 

[runswithsizzers]

You say, "I have problems keeping negatives eg Tri-x and any 6 x 6 flat." - what do these problems look llike?

The reason I ask is, I have photographed both 135 and 120 film with a digital camera using nothing more than a piece of matt board with a cutout for the negative layed on top of the film, and I never noticed any problems due to film flatness. Yes, I could see the film was slightly bowed, but at f8 and smaller apertures I had enough depth-of-field, and my images were acceptably sharp, including the corners.

If you can't get both the center and corners of the frame sharp, then it may be that your lens has too much curvature for flat work(?)

It might help to know:
what lens are you using?
what aperture are you using?
what magnification are you using?

 

[Bobby Brewster]

Thank you @runswithsizzers That makes sense. As a newbie to this my technique is probably suspect.

I have now acquired a dedicated Canon 100mm f2.8 ( non-L ) macro lens which I will try out next time I scan. If I have that on my R5 it should be pretty much 1:1 and yes I will stop it down to f8 or f11 when I take the picture

 

[runswithsizzers]

Good! Let us know how it works for you.

 

[Bobby Brewster]

I will thank you. I’ve been on a bit of a spree this week and I have to rein in the expenditure so hopefully this lens will do the job.

 

[Lemmythink]

I will thank you. I’ve been on a bit of a spree this week and I have to rein in the expenditure so hopefully this lens will do the job.

How did it go?

 

[JerseyDoug]

I have had good luck holding both 35mm and 120 negatives flat for digital camera scanning using DigitaLIZA scanning masks. They are very affordable compared with other solutions.

 

[Bobby Brewster]

Hi again.

I have the lens set up and so far I've only used stopped down to f11 for 35mm negatives with which it did the job admirably.

I have held off on the glass until I have tried medium format but I now have an "Essential Negative Holder" and I have a roll of 120 Fomopan in camera which I will have finished soon.

I'm hopeful this will sort it