Last time I talked about salt printing, and how I used a inkjet printed digital negative to use for the contact print. Today I’ll show you how I made the negative and the printout.
This is the first time I tried making one of these negatives to use in my first salt-printing attempts, so I am not claiming this to be the best, most accurate or most technically insightful of tutorials – but it seemed to do the trick.
What you need to make a digital negative:
- digital image
- (Pictorico) OverHead Projector Film (OHP)
Step 1: Choose an image. Select a file that is large enough for the size of the print-out you intend to make.
Step 2: Open up your image in your image editing software (Lightroom, Photoshop, GIMP) and edit it as you would normally do. I usually stick to spotting for any dust that may have gotten onto the film whilst scanning and adjusting the levels in Lightroom. Save your image.
Step 3: With your image opened, save the file under a different name, so you won’t accidentally save over your original. I’ve done the next few steps in Photoshop.
Step 4: Make the image 16 bit & RGB. You can do this under Image > Mode > 16 bit / RGB in Photoshop.
Step 5: Apply a ratio curve to the image, invert the image and flatten. Don’t worry too much about how messed up your image is looking right now – but try to judge the contrast that it will provide to your print. The contrast I’m showing here is actually not that great, but it’s a good example of a 1:1 image conversion.
Step 6: Add a new layer, set to ‘screen’ mode.
Step 7: Using the colour picker, set the foreground colour to:
Platinum printing (density 1.6) R: 127 G: 255 B: 0
Palladium Printing (density 1.9) R: 70 G: 140 B: 0
(some) Palladium printing (density 2.2) R: 50 G:100 B:0
Salt and Albumen printing (density 2.5) R: 25 G: 50 B: 0
Step 8: Fill the new layer with this colour. The idea is, that some colours block out UV light better than others and you’ll see in a cyanotype printing video I’ve linked below, that red is their colour of choice.
Step 9: (optional) Taking the advise from another website (see links below) I added a step tab, so judge my exposure times. You can find a few via Google, but you could also opt for a classic exposure test by making a test strip.
Step 10: You are now ready to print your negative! Fire up the printer and insert one of your OHP sheets. The ‘sticky’ or non-slippery side is the one taking the image. Insert it with the paper strip first so your printer has something to hold on to. Print with the following settings if you have the option:
Working space: adobe RGB / US web coated (SWOP) Gamma Grey 2.2, Dot Grain 20%
Policies: Convert to working (all) – tick all boxes
Conversion: Adobe (ACE), perceptual – tick all boxes
Leave your print to dry for at least 24 hours.
As I did not believe that the above negative would have made a great print, I went back and made some changes in the original to bring out more detail in the shadow areas. Other than that, I followed the same steps as outlined above, resulting in quite a different negative!
Should you like to learn more about making a digital negative, I can recommend having a look the following sites and articles: