Curve corner – Photoshop and Gimp curves for making digital negatives

A curve could be described as the representation of all the tones in an image, from highlights to shadows. Photoshop and Gimp curves are a great tool for creating a balanced digital negative. They help you control the tonal values and contrast of an image or a digital negative. Download ready-made curves here – or upload yours to share with others.

Collator / Malin Fabbri
Contributors / Jim, Grace Taylor, Clay Harmon, David Hatton, Frank Gorga, Gimp curves by Matthew Miller


Send us yours! Email talk (at) alternativephotography.com

You can of course adjust the curves to adjust them depending on how you manipulated your photograph or which paper you will be printing it on. All the same, they are a good starting point.

If you have problems downloading the curves:

  • On a PC: Right-click with the mouse on the link and select “Save Target As”
  • On a mac: Hold down the Ctrl key and click on the link. Select “Download Link to Disk”.
  • Browser problems: If you get a lot of funny signs, like these: ������&� when you try to download a curve, it may be a browser problem. Try another browser.

Specific about Gimp curves: If you are using Gimp your curves need to be put in /.gimp-2.*/curves/ under your home directory.

Input valuesOutput valuesThe cuprotype / salt print curve

Cuprotype curve & Salted paper printing curve.

Added March 2023 by Frank Gorga

Download cuprotype / saltprint curve Cuprotype.acv here.

Input values
0
13
27
38
51
64
89
115
140
166
191
204
217
229
242
255
Output values
0
15
21
24
29
33
40
48
61
81
110
132
169
204
230
255
Salted paper and cuprotype curve

This curve is essentially the same as described for salt printing in Christina Z. Anderson’s book Salted Paper Printing. A Step-By-Step Manual Highlighting Contemporary Artists

A Cuprotype by Frank Gorga made using the Cuprotype / Saltprint curve (the print is also toned)

Cuprotype with Simple FeCN toned then Iron toned
Cuprotype with Simple FeCN toned then Iron toned

Download curves for cyanotype negatives in Photoshop and Gimp

These curves are from 2010 and may no longer work, if you have the time, do try and please give us feedback.

Cyanotype negative curve

Cyanotype made using the curve

Cyanotype curve

by Jim.
Click here to download the curve for Photoshop
Click here to download the curve for Gimp
The curve should look like this:
Cyanotype photoshop curve in rgb
Cyanotype photoshop curve in cmyk

Jim Read Cyanotype using cyanotype curve

Download gumprint curve for Photoshop

Gumprint curve

Gumprint made using the curve

Gumprint curve

by David Hatton.
Click here to download the curve for Photoshop
The curve should look like this:
Photoshop curve for gum bichromates
Gumprint curve in cmyk

Gum bichromate made using the photoshop curve

Note from David: The curve is applied before inversion to a negative and the image should be RGB.

When printing these negatives the overall density of the ink laid down can be increased, whilst keeping the densities relative to each other, by using the photoshop ‘Apply Image’ function set to multiply. This gives better exposure control for me as I use the Sun as my lightsource.

Numerical values: INPUT – OUTPUT
2 – 32
6 – 67
10 – 75
14 – 76
26 – 83
47 – 90
72 – 99
101 – 107
127 – 116
152 – 126
177 – 136
200 – 150
219 – 168
233 – 188
245 – 224
255 – 255

Download photopolymer curve for Photoshop

Photopolymer curve

Photopolymer made using the curve:

Photopolymer curve

by Jim.

Click here to download the curve for Photoshop

Read Jim’s article on Photopolymers.

The curve should look like this:
Photopolymer photoshop curve in rgb
photopolymer photoshop curve in cmyk

Photopolymer using the polymer photoshop curve

Download platinum curves for Photoshop and Gimp

Platinum print curve

Version 2 of a platinum print curve

Platinum print curve

Click here to download the curve for Photoshop

Click here to download the curve for Gimp

The curve should look like this:
Platinum photoshop curve in rgb
Platinum photoshop curve in cmyk

Platinum print curve version 2

Click here to download the curve for Photoshop

Click here to download the curve for Gimp

The curve should look like this:
Platinum curve for gimp
Platinum gimp curve cmyk

Download ratio curve for Photoshop

Curve for a variety of processes

Image made using the curve

Ratio Curve

By Clay Harmon – works for both Platium, Albumen and Saltprints.
Read more in Clay’s article

Click here to download the curve for Photoshop

The curve should look like this:
Curve for negative in rgb
Curve for negatives in cmyk

With a positive ratio
Positive of “Paris Chairs”.

With a negative ratio
Negative of “Paris Chairs”.

Download vandyke curves for Photoshop and Gimp

Vandyke curve

Vandyke print made using the curve

Vandyke curve

by Grace Taylor.

Click here to download the curve for Photoshop

Click here to download the curve for Gimp

The curve should look like this:
Vandyke photoshop curve in rgb
Vandyke photoshop curve in cmyk

Vandyke print using the phtotoshop curve

Vandyke curve

by Jim.

Click here to download the curve for Photoshop

Click here to download the curve for Gimp

The curve should look like this:
Vandyke brown curve in rgb
Vandyke brown curve in cmyk

 

How to import a curve in Photoshop and apply to digital negatives

Importing a curve is easy. Just load the curves menu.
Upload a curve in photoshop

Then press “Load”:
Load a curve in photoshop

Select the right curve:
Select the right file in photoshop

That’s it!

 

How to save your curves in Photoshop

You can adjust the curves or create your own by pulling the centre or one of the handles at the end:
Save your curves in photoshop

When you are happy with the settings you have and want to use it for another photograph, just save the settings:
Save curves in photoshop

That’s it! Now you can reuse it next time you want to make a negative.

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Recommended reading on Negatives
Calibration for Alternative Photographic Processes by Calvin Grier
Buy directly from the author

Calibration for Alternative Photographic Processes

by Calvin Grier

A 4-part series on getting your alt. proc. prints right. Become an expert calibrator.
 

Digital Negatives with QuadToneRIP: Demystifying QTR for Photographers and Printmakers

Digital Negatives with QuadToneRIP: Demystifying QTR for Photographers and Printmakers

by Ron Reeder and Christina Z. Anderson

Fully explores how the QuadToneRIP printer driver can be used to make expert digital negatives.
 

Precision Digital Negatives for Silver & Other Alternative Photographic Processes

Precision Digital Negatives for Silver & Other Alternative Photographic Processes

by Mark Nelson

An eBook describing Color Density Range Control.
 

The Negative (Ansel Adams Photography, Book 2)

The Negative (Ansel Adams Photography, Book 2)

by Ansel Adams

Devoted to a discussion of light, film and exposure.
 

24 thoughts on “Curve corner – Photoshop and Gimp curves for making digital negatives”

  1. I am trying to download the cyanotype curve on my macbook air but it won’t download. I click on ‘download the curve for photoshop’ holding down the ctrl key and there is no option to ‘download linked file to disc’, just ‘download linked file’. Photoshop doesn’t recognise the file. Any ideas? Thanks.

  2. I have done some Gum printing, and in my experience, if you apply the curve to the image before inverting the image into a negative, you will be decreasing the destiny of the negative which you don’t want to do because it will make it harder to print. While the curve makes the image/photo darker, it will make those now darker areas lighter when you convert to a negative. This makes the negative thinner and harder to print with a wide tonal range. My method is to make any image adjustments then do the color separation, and then apply the curve to each color channels negative for the gum method to adjust the contrast profile to performance characteristic of the method. This should help to increase the possible tone range of your prints.

  3. Would either of the two Platinum curves shown here be a good starting point for Pt/Pd? If so, which one? Thank you.

  4. Who authored the Platinum curves that are just below Photopolymer curve? It is unsugned in contrast to all other curves that here…

  5. I could not find any curves for carbon gelatin transfer prints. it seems no one has these curves.

  6. I’m having problems with the Van Dyke curves. I downloaded them however they do not download as a file I can use. They download with a printer icon instead. It downloads as an atf file and then when I try to load the file it closes my PS down. I’m working off PS6

    I also do not have the same screen load options as shown above.

    Could you help me with getting the correct Van Dyke curve.

    Thanks
    Shelia Maciorowski

  7. @admin – the gum curve specifically says to apply it BEFORE inverting to a negative but the rest do not. So was your answer to Christian saying that all of the curves are set up to be applied to the image before inversion or just the gum curve?
    Thank you.

  8. @Susan In Photoshop CS4 you can add the ACV file into a presets folder. I managed to do this on a Mac by adding a curve file to this folder:

    Applications > Adobe Photoshop CS4 > Presets > Curves

    I’m guessing you could probably do something similar on a Windows machine by going to “Program Files” and looking for a similar folder.

    Once you restart Photoshop, the curve should appear in the dropdown list at the top of the curves dialog.

  9. @Susan… not actually sure. Let me know what you find out, and I’ll see if it’s possible to convert them to CS4…

  10. I downloaded the David Hatton gumprint curve but can’t seem to load it into photoshop CS4. In fact the curve dialog box does not have a load button on it. Don’t know if this is a CS4 thing or what. If I had the input and output points on the curve I could do it manually I think. Suggestions?….

    Thanks

    Susan

  11. I agree, but the curves are meant to be a starting point, not a definite guide. If you have never used curves, it’s a hint of what may be right.

  12. please don’t encourage people to use canned curves. Each image and process deserves its own care. No curve works for two different images equally well. Using curves is all about understanding the tones in the image, and making a curve that places the tones where you want for the final print. It’s not about using one curve per process!

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