Question About Digital Negatives for Salt Prints

Hello - new here and recently started experimenting with digital negatives for salt prints.

I am unsure if I am thinking about my final print latitude options in the right way. I know through step wedge prints that I can reach max print density at 16 minutes (through a blank sheet of Permajet DTF), but that if I let a print run to max density there is not enough blocking with the standard inks to hold highlights well. I have run through the process of finding the best colour for blocking (a red) but it is still black that provides the most UV blocking.

The result of this is I seem to have a choice, max black but fairly dense highlights, or brighter highlights with blacks nowhere near max.

I realise that specialist ink would improve this, but I am not willing to go that far at the moment. I just want to check that my analysis of the situation is correct, and if there is anything I can do about it without specialised inkjet equipment?

Many Thanks
Jules.

Welcome aboard, Jules!

Your analysis is correct. The bad news of this is that with your current printer and inks, you will not be able to produce salt prints that exhibit a full range of tones between dmax and paper white, so you'll have to compromise.

You could experiment with overlaying two or more negatives, but this will affect sharpness in the print, and it's just a chore to begin with.

If you happen to like alt. processes like salt prints and decide to stick with it, I'd recommend at some point to move to a different way of making negatives. Either purchase a more suitable (pigment) printer, convert your current printer by using more suitable inks (e.g. UV blocking inks made for screen printing applications) or explore silver gelatin negatives (large format camera or enlarged small format negatives to large format film).

One thing to try for more UV density:

1. Duplicate your image layer.
2. Invert the bottom layer to the best blocking colour.
3. Invert the upper layer in monochrome, but limit the densest black to about 98%.
4. Set the upper layer mode to multiply (in Photoshop) or luminance (in GIMP).
5. Export and print.

This should give you a higher UV DMax than colour or black alone, and might get you where you want to be.

I don't use PhotoShop, so there might be a better choice than multiply in that app.