I'd like to pose another question along the lines of the previous one. Is anybody using the ink jet printer to make negatives on transparency film, or other media, to use for contact printing? Any advice? Tips?

Thanks - chris

-- Christian Harkness (chris.harkness@eudoramail.com), March 30, 2000

Answers

As much as I dislike digital, that is an interesting concept, I would be curious to know how it works out, printing times and sharpness, ect. Pat

-- pat j. krentz (krentz@cci-29palms.com), March 30, 2000.

I would guess that there are a few issues:

1) Resolution: Today's inkjet printers have resolutions of up to 1440 dpi. That would be less than 60 dots per millimetre. Maybe I am thinking along the wrong line, but I would guess that can't make for a resolution of much more than 15 line pairs per millimetre. I don't know whether that is sufficient. I am not sure about the number (I read it somewhere, but the old brain is not what it used to be.), but I believe a print should resolve something in the order of magnitude of a hundred line pairs per millimetre to appear sharp.

2) Density: This seems much more critical. I am very doubtful as to whether ink is capable of producing a density range of say 1,5 log density units.

3) Tonality: Modern inkjet printers are capable of producing a surprising range of tones, but those tones are patterns of black dots and white "no-dots", which means they are created at the cost of apparent resolution. The above estimate for the resolution just considers the resolution for black/white contrast. So the gray-scale resolution is worse.

4) Why bother? If you can create the negative on your inkjet printer why not the print? The only reason I could imagine is permanence of the print. A silver/gelatin print is of course more permanent than the inkjet print.

So basically, I am not very optimistic that this works, but as I am curious, please let me know the results if you test it.

-- Thomas Wollstein (thomas_wollstein@web.de), March 31, 2000.

Hi - I will pursue this, and if/when I find out anything of substance I will post it here. Thanks for everybody's input.

Please keep adding comments if you are interested in the subject!

Thanks - chris

-- Christian Harkness (chris.harkness@eudoramail.com), March 31, 2000.

I have a friend, Catherine Streinmann, who has been making great ink jet prints for platinum printing. I am extremely impressed with her results as she is only using a basic Epson Photo six color printer. The trick seems to be in using all six colors. Her negatives are multicolored full sheets. She has certain profiles worked out for certain color settings for different transparency stock. It seeems pretty complicated to me. She has been working with a guy who is teaching her the system.

If there is interest, I'll ask her to send me or the forum some details. Frank

Check her out at:

http.//www.catherinesteinmann.com/

Check me out at:

http.//www.culturalvisions.com

-- frank Ward (frank@culturalvisions.com), March 31, 2000.

I've always thought it would be interesting to use a computer to produce something like a contrast mask, but which would allow you to selectively dodge some parts of the image with more control than you can accomplish by hand. In this application, a large Dmax should not be critical unless you require considerable dodging. However, I think scaling and registering the image precisely might be challenging.

-- Matthew Hunt (mph@astro.caltech.edu), March 31, 2000.

"I believe a print should resolve something in the order of magnitude of a hundred line pairs per millimetre to appear sharp." According to John Carroll in his book "Image Clarity", an 8x10 print (viewed at normal distance) with 3 lp/mm resolution is generally perceived to have "adequate" sharpness, anything over 7 lp/mm is perceived to be "excellent".

-- Tim Brown (brownt@ase.com), March 31, 2000.

Hi Frank, yes I think there seems to be quite a bit of interest in this. So, if you could ask Catherine for any info she might be able to provide, I think that would be great. Many thanks!!!! - chris

-- Christian Harkness (chris.harkness@eudoramail.com), March 31, 2000.

According to Ctein, in his book "Post Exposure," 30 lp/mm resolution is required in an 8x10 print for "perfect" sharpness. He also reports that a typical RA-4 color negative paper can reproduce around 65 lp/mm.

-- Sal Santamaura (bc_hill@qwestinternet.net), March 31, 2000.

I am reading a great book with tons of advice on the subject, the book recomends outputting random dot negatives on a high-end agfa imagesetter for all types of traditional and non-silver contact prints. The book is at the studio right now so I will post the name of the book in a day or two. Also included is a CD with lots of printing profiles, and contrast tweeks to get the right negative... one way to get around the limitations of inkjet printer resolutions is to print more than one negative (one negative for shadows, one for highlights)the random dots merge producing an image of even higher resolution! more later...

-- Abel Sanchez (bigfilmfoto@aol.com), April 05, 2000.

Here is a web site that addresses making digital negatives for contact printing.

http://danburkholder.com/

chris

-- Christian Harkness (chris.harkness@eudoramail.com), April 05, 2000.

The best book on the subject is by Dan Burkholder, "Making Digital Negatives." It's a great reference and hot-to.

-- Jim Steele (jdsteele@erols.com), April 06, 2000.