How to test the lpi of cyanotype printing?

[feppe]

I attended a workshop for cyanotype printing, and was very surprised how simple it is. I was expecting volatile solutions, breathing masks, and guesswork of a result at over 50% failure rate. Looks like much more reproducible than I was expecting.

Is there an easy way to test how many lpi I can get from a certain paper with cyanotype? Mainly curious, as obviously I can (and will) just do some photographic prints as well.

[koraks]

Well, testing it would involve making some prints on different paper, so you'd end up doing that anyway. I found that with a good contact frame and a smooth paper, I could print the individual dots of an inkjet negative printed at 1440dpi with an Epson 3880 printer, suggesting the cyanotype process in any case outresolves an inkjet print. However, I personally like my prints on a but more textured paper better even though the resolution is lower. I think the texture creates some kind of acutance that has more impact on the appearance of the print than the actual resolution.

[feppe]

Wow, wasn't expecting it to be nearly that high!

I'll probably just do some prints of my photographs and make contact prints that way. I've never shot negatives, so would have to invest in darkroom equipment and chemicals if I go that route...

[koraks]

You don't need a darkroom to process negatives; a changing bag or light sealed closet and a daylight development tank will do just nicely. The initial costs of doing b&w 4x5 negatives are something like €120 (not including camera and film). But especially with classic cyanotype, inkjet printed negatives on transparencies work just fine as well! I personally switched to silver negatives because I wanted to get rid of the inkjet dot pattern in my prints; sometimes, the resolution of contact printing processes is actually a disadvantage - you see every tiny defect or imperfection in your negatives ;)

[Jim Jones]

Resolution will be affected by the printing technique as well as by the materials used. A small light source some distance from the printing frame and very intimate contact between negative and paper improve resolution. A large light source close to the printing frame and poor contact can decrease sharpness.

[koraks]

Particularly poor contact influences it. I use a light source larger than the print at a distance of a few inches. Prints are tack sharp on smooth paper.