software for stochastic screening on my Epson 2880

[David F]

I would like to print a stochastic screened image onto transparency film, using my Epson 2880 inkjet printer. I need better quality and control than I can get printing bitmapped images. I've seen one software program called IceFields, but this has to run on a Mac and is a bit pricey.

Any suggestions? Thanks, David

[Stephen Marsh]

What is wrong with the native Epson FM screening? Too fine?

I was going to suggest IceFields, however you asked for another option. What do you mean better than "bitmapped images"? Photoshop stochastic bitmaps? I only know of one other option without doing a search:

RASTUS export plugin


Hope this helps,

Stephen Marsh

[gordo]

You could try Andromeda Software's Screens package for both PC and MAC.
Andromeda Software, Inc. Store

They don't provide much info on their website, but I have a very old MAC OS 7 version that had some interesting FM-like screen effects with lots of user control. If the latest version is anything like that it might do the trick for you.

best gordo

[M&M Displays]

What are you using the film for? Burning screens?

[David F]

Yes, I'm using it for exposing plates.

Since I'm on a PC, Icefields won't work. I don't know what you mean by Epson FM screening, but the only way I know of controlling the resolution of the dot pattern on the my desktop printer is to print out at "draft" quality, which doesn't give me the results I want.

I think of the stochastic screening to be different than bitmapping, and the bitmap option in Photoshop again doesn't give me the control I need.

I'm considering using this software to create transparencies for exposing polymer plates for printing on an etching press. The idea is the random dot pattern from the stochastic screen, printing onto transparency film, creates a matrix of indentations when you use it to expose the plate, which holds ink, which in turn you use to print onto a sheet of paper, hopefully producing an image with a range of tones.

What is wrong with the native Epson FM screening? Too What do you mean better than "bitmapped images"? Photoshop stochastic bitmaps? I only know of one other option without doing a search:

RASTUS export plugin

[David F]

Thanks Gordo. I heard of this plug in years ago, but at the time I think it only worked for Mac. I'm working off an earlier version of Photoshop, so I've emailed them to see if their plug-in will work with my version.

Best, David

You could try Andromeda Software's Screens package for both PC and MAC.
Andromeda Software, Inc. Store

[Stephen Marsh]

I don't know what you mean by Epson FM screening, but the only way I know of controlling the resolution of the dot pattern on the my desktop printer is to print out at "draft" quality, which doesn't give me the results I want.

Inkjet printers use a stochastic screening/frequency modulated (FM) screening pattern. The Photoshop diffusion dither bitmap screen is dependent on the image resolution, the higher the resolution the finer the dots.

Have you had a look at the Rastus plug that I linked in my previous post? It has a demo version available for MS Win or Mac and has been used for similar processes as you intend.

You will likely need to develop some extreme compensation curves, to hit the data with before turning it into an FM screen (these would probably lighten the image from the midtones to the shadows).


Best regards,

Stephen Marsh

[David F]

Thanks Stephan, I think I tried Rastus quiet a while ago; I'll look again. Best, David

Have you had a look at the Rastus plug that I linked in my previous post? It has a demo version available for MS Win or Mac and has been used for similar processes as you intend

[graficworx]

Depending on what type of photopolymer plate you are using they typically range from 90 to 133 line screen, or roughly 1200 to 1800 dpi. You would need to work in this range to get a good image. If you set the printer at max resolution, and then send it a photoshop prepared file that's, for example, 90 line screen, you should get something close to 90 lpi. The printer driver will interpolated down resolution, but never force the resolution higher, only interpret it. In draft mode your probably getting 30 lpi at the max.

[David F]

Thanks Graficworx. I'm using Toyobo Printight plates for intaglio-type printing. Usually I use a two-exposure method with an aquatint (e.g. stochastic) screen, then the image transparency.

I was just considering trying the one-exposure method, which requires that you add the "aquatint" directly to the image. I will try the Rastus program for this--it allows you to set input and output resolutions. So, based on your information, I would set the output resolution to about 1200-1800 dpi?

Thanks, david

Depending on what type of photopolymer plate you are using they typically range from 90 to 133 line screen, or roughly 1200 to 1800 dpi. If you set the printer at max resolution, and then send it a photoshop prepared file that's, for example, 90 line screen, you should get something close to 90 lpi.