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Step wedge image file?

RogerHyam

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I'm just about to crank up Photoshop and make myself a step wedge to help with my salt and cyanotype printing. There are some nice tutorials on YouTube on how to do this but it will take me a while and I don't enjoy messing with Photoshop. I spend enough time on computers for work.

Why can't I download one from somewhere? Am I missing something? There are a bunch of tutorials on how to make these things but it only needs to be done once by one person. Why do we all have to do it individually?

Would anyone like to share their step wedge image file or know of the location of one?

[ I looked at buying a Stouffer 21 step step wedge but they are £24 here in the UK - double the US price. I have a printer sitting here and some acetate and don't need anything too accurate. Plus I'm tight and that is 24g of Silver Nitrate or a big pad of water colour paper. ]
 
First of all, get the Stouffer; it is worth the money. Nothing beats a professionally made wedge.

Second; just fill the amount of rectangles you want to measure with corresponding RGB value? Or is here something I don't quite understand?

Here is my 5x7" calibration sheet if it helps anyone ..
 

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if you are using film to make your salt prints rather than digital negatives it really is better to get the stouffer. Transmission of digital negatives vs film is wildly different and step wedges /exposures behave differently with salt paper than regular silver gelatine paper.

To be honest I dont think a step wedge really tells you much anyway with salt prints. Its probably just as instructive to print an image in a UV printer for 5 mins, 10 mins, 15 mins, and 20 mins (for example) and compare the 4 prints to observe what happens with exposure.
 
Film density is film density. Ink density inkjet-printed onto transparency material will behave in a somewhat different manner. Plus you'd have no standardized way to precisely calibrate the download to the working version itself. Craig just gave the gist of it. ... And the notion that a downloadable color chart printed with inks might be OK for soup can labels or colored name tags on a dog collar, but hardly seems like a realistic photographic tool. Get a seriously engineered and time-tested MacBeth color checker chart instead; they actually knew what they were doing.
 
 

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Here is the one I use...



I can't give credit to the originator as I have have no clue where I found this a decade or more ago.
 
alternativephotography.com has one, attached to an article by Christina Z. Anderson about digital negatives. The easy digital negatives web site has one, too.

I assume you want to make digital negatives. If not, then you'll need a Stouffer, as suggested above. Actually, a Stouffer wedge is really worth having as a reference point, even with digital negs.
 
+1!
 
DREW WILEY said:
Film density is film density. Ink density inkjet-printed onto transparency material will behave in a somewhat different manner. Plus you'd have no standardized way to precisely calibrate the download to the working version itself.
Click to expand...
This is the problem with DIY step wedges. The only way to work around it is to calibrate the DIY step wedge with a transmission densitometer.

Besides, most inkjet printers don't give sufficient density for a step wedge that's to be used with alt. processes except for classic cyanotype.
 
koraks said:
Besides, most inkjet printers don't give sufficient density for a step wedge that's to be used with alt. processes except for classic cyanotype.
Click to expand...

Following this logic most ink jets don't produce negatives with enough density to do alt process. So digital negs wouldn't be feasible for salt. (This is academic for me as I'm not interested in digital negs).
 
Thanks to everyone for your replies. There is stuff to think about and try here.

I'm not doing this for digital negatives but for printing my own silver gelatine plates. Maybe I should investigate making a step wedge with my own emulsion and check the densities with my spot meter.
 
RogerHyam said:
Following this logic most ink jets don't produce negatives with enough density to do alt process. So digital negs wouldn't be feasible for salt. (This is academic for me as I'm not interested in digital negs).
Click to expand...
In my experience this is correct. I found digital negatives entirely dissatisfactory in several ways. Many of the "successful" results I've seen online also suggest a gross lack of density in digital negatives. The exception are negatives made with modified printers and inks specifically intended for this purpose.
 
RogerHyam said:
Maybe I should investigate making a step wedge with my own emulsion and check the densities with my spot meter.
Click to expand...
If you insist in diy, I would suggest using regular b&w film or perhaps ortho or xray film for this purpose. With an enlarger and a decent timer you could get pretty decent results. I'm not sure about the reliability of a spot meter as an absolute reference if film density though. You'd still need an absolute reference to calibrate your step wedge against, I'd say.
All considered I think the sensible solution really is to invest the modest amount of cash in a stouffer wedge. They're not all that expensive and DIY-ing a good one will take quite a bit of time and experimentation.
 
Roger, just buy a CALIBRATED step wedge with the densities of each step supplied with it, measured with an actual densitometer. They're quite affordable! A spot meter isn't the appropriate instrument for that. Then you can visually compare densities in your own negs if necessary. Don't make all this way more complicated than it needs to be. But for actual analytic work like plotting curves, then there simply is no substitute for a transmission densitometer.
 
DREW WILEY said:
Roger, just buy a CALIBRATED step wedge with the densities of each step supplied with it, measured with an actual densitometer.
Click to expand...

For hobbyist I've understood the Stouffer calibration is waste of money. It is just the same wedge as others but comes with invidual calibration sheet for the selected wedge?
 
How can it be a waste of money if it only costs you about as much as three or four rolls of 35mm film? The price of a calibrated one is just a tiny amount more than an uncalibrated one. If you need a wedge, do you want to spend a month or two fussing around trying to make your own, not even understanding exactly what it is supposed to look like? Stouffer wedges are very carefully made in a standardized highly linear manner. As a "hobbyist" you can do anything you wish, and waste as much time, paper, and money as you wish trying to get from Point A to Point B. A step wedge is just a tool or convenience to help you get there more efficiently.
 
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Could you explain in more detail? What issues arise when the density of a digital negative is insufficient? I understand that each technique has its characteristics, but I would like to know if there are any problems that can’t be resolved even with linearization.

Also, I’ve heard that Pictorico digital negative film can be printed with high density. However, I use a cheap printer (dye-based inks), so I don’t think I’ll be able to make high-quality negatives just by using Pictorico digital negative film.
 
D_Quinn said:
Could you explain in more detail?
Click to expand...

Yes, and I have to set something straight. Digital negatives can have sufficient density for alt. processes. I was wrong back in 2021, mostly because I was used to a particularly poor transparency material that just didn't work well. Generic screen printing inkjet film works fine, as does Pictorico, Fixxons etc.

D_Quinn said:
if there are any problems that can’t be resolved even with linearization.
Click to expand...

Linearization and absolute density are different things. The darkest parts of the negative need to have sufficient density to block all exposure. Linearization is about how the tonal values are spread between the darkest and lightest points. You generally set the print process parameters first, then determine the maximum density needed in the negative to get pure paper white with your printing process, and then proceed to linearization. But there are a couple of approaches towards linearization that may deviate subtly from this.

D_Quinn said:
I use a cheap printer (dye-based inks)
Click to expand...

That's in general not a very good starting point. While it's definitely possible to make dyes with excellent UV blocking characteristics, the dyes generally used in color printers are not particularly good UV blockers. Pigment printers overall work better for this end. Since you're doing salt printing, which puts rather high demands on negative density, this may be a concern.
As I pointed out in your other thread, start by determining the exposure for your salt print process that gives the maximum achievable black. Then test if your inkjet printer can lay down sufficient UV density to give pure paper white.
 

Whether you can use your printer depends on the processes you want to print with, and the brand of printer. From first hand experience I can tell you that HP dye inks will deliver more than enough density for any process; other brands might limit you to processes that need lower UV densities. You can easily test your printer with some cheap generic film and a bit of work.
 
@koraks
@revdoc
Thank you for the detailed explanation. Yes, with a step wedge, I was able to achieve maximum black in about 10 minutes. The gradient shows steps 3 through 17 clearly.

Regarding digital negatives, I did think a pigment-type printer would be more suitable. I used to have one, but I was constantly dealing with clogging issues.

I understand what you’re saying. I printed a chart on both OHP film and Pictorico and found that the highlight density (the darkest areas on the negative) was indeed higher on the Pictorico, which gave better whites in the print. I’ll try printing the same chart on Pictorico with a pigment printer and compare the results.
 
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