Mike Chaney's Tech Corner

I have been calibrating some non-Epson papers with my new R2880.  Ilford Smooth Gloss and Pearl both come out with a slight red bias (as does Ilford Galerie on my Canon i950).  This is easily corrected with the editing function; minus some magenta and plus a little cyan and yellow.

However, I have also purchased some Lyson Pro Photo Gloss and this requires massive brightness correction, so much so that I cannot get the right hand edit image fully to match the print.

This paper is way whiter than white which makes me think it may have a lot of optical brightener in it.  My scanner (Epson Perfection 4870) light source is cold cathode which has a high UV output which will make the OBA fluoresce really well and I am wondering if this combination is distorting the result.

Could this be the cause?

A friend I discussed it with last night suggested I might try photographing the targets with my 21 megapixel DSLR using ordinary daylight or even tungsten.   Could this work?

If this is what is going on, it occurs to me that it could be overcome by making a reference scan of a blank sheet of paper before scanning the targets and including some kind of white correction in the software.

Or is caused by something completely different and silly that I have done?  All suggestions welcomed.

You probably already know this, but there is no such thing as "whiter than white".  A lot of optical brighteners just make the paper blue instead of white, and yes, that can certainly distort a profile!  The best thing you can do is make sure your scan of the targets doesn't have any (or at least very little) clipping.  You may be able to get a good photo of the targets using your dSLR but that's usually more trouble than it's worth because then you have to deal with uneven lighting caused by both the light source and the lens (the photo will be darker toward the edges due to the lens) and the fact that all lenses have some degree of distortion that can make the color patches very difficult to align.  The best you might be able to do is make sure you scan such that you don't clip the highlights.  You can try the dSLR and if you can get things lined up and you can get very even lighting, that can work too.

Mike

Thanks for that.  I thought it through a bit more and think I found the answer.  Originally I used the "Bright" target which is recommended for prints from the Epson Stylus Photo R2880.  I did it again using the ordinary target and the first print came out with the slight red tint that seems to run through all my scans, plus a rather higher contrast.  It was easily edited to a satisfactory result.

Hope this is useful.

I fought magenta casts in Ilford pearl for years and finally gave up on it.  I don't know what causes it.