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Noritsu 2901 X-over in B&W


rob99

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We are having a problem printing B&W on our 2901. With the midtones and shadows neutral we get pink (banding) in the highlights (although the pure white is still white) . We have not been able to get any satifacation from Kodak/Noritsu in Ausralia as yet. Any ideas?

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This is normally caused by incorrect reading from the colorimeter.

If you look at the emulsion test print do the first couple of steps look pink?

Check the silly things first, such as the wire being trapped underneath the colorimeter head causing it not to sit flat.

Sometimes just cleaning the colorimeter drive roller and calibrating the stop position will resolve it.

Other cause could be the calibration plate is scratched/ damaged.

Sometimes the pressure spring can break on the colorimeter advance unit, if you remove the colorimeter head, you should see a black plate that is sprung (pushes the print towards the colorimeter head) gently push it with your finger to check it is still sprung.

Or the actual colorimeter head itself is faulty.

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In reply to rob99:

When you say banding do you mean lines as in Ink Jet or do you mean that certain tones get a cast to them?

I'm assuming the later.

We get this everytime a manufacturer changes it's paper and Noritsu play catch up by shrugging their shoulders and announcing that they don't support the new paper.

Our short term solution, now we are aware of the problem is not to do a weekly setup.

This is obviously not a good solution long term and doesn't help if you already have the problem.

This is the situation we are in currently with Fuji having brought out new crystal archive which Noritsu don't support. There is a slight overall cast that is sorted by dialling in one click of colour.

The next solution is to do daily and weekly balancing on a paper that they do support. We found that as long as that is done, all non supported paper will come into line as normal with emulsion number changes.

Sometimes when there is a paper type change we find that areas of high frequency eg a radiator grill or other fine mesh that we get a colour appearing in there but no where else. To sort this is to perform a black balance. According to the help files this also is useful if you notice colour fringing around areas of black.

The one we haven't been able to solve yet is that we get good results on gloss emulsions but that matt seems to suffer from a slight yellow in the non white highlights. Probably a bit like your pinks but only on matt. Not major but just enough to be annoying.

If anyone knows how to sort that one I'd love to know.

HTH

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I understand there are different versions of the colorimeter head.

If you remove the head (as you do for a monthly setup) look underneath there is a letter after the model number, most are M or N the later the letter the better the response.

So a letter Z for example is going to be more accurate than a letter A model.

Matt and gloss papers always seem to read slightly differently, I think the grain of the matt paper causes problems, especially with the subtle shades.

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  • 2 weeks later...

Thanks Guys for all your suggestions, it has taken a while to work through them. Kodak (from whom we purchased the machine in Australia) has now replaced the colorimeter head (P-series) and the cal patch and the problem has been significantly reduced. We still believe there is still a small magenta/green crossover but not sure if we can go any further. What showed our problem most clearly was from a grey gradient file we made from white to black which initially showed a distinct band in the highlight end with the green to magenta shift this was smoothed out significantly and color shift reduced significantly with the new head.

Again thanks for your help

Rob

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