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Author Topic: Help troubleshooting a magenta cast  (Read 12543 times)
nbagno
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« on: October 11, 2013, 05:16:21 AM »

Below is a picture of part of a print on Epson presentation paper matte. The image is a 6x9 B&W film negative scanned using a leafscan 45 which used a ND filter when scanning so it's a total monochrome image from the start. I did some adjustments in photoshop and lightroom and used some third party filters (Nik).

You can see there is a magenta cast above the head and down the left arm. The color cast is not there with I review the image in Photoshop, lightroom or Qimage. This issue is not isolated to just this image, I have at least one other in this current print run that is doing the same thing. However with both I have made a successful print at least once, the last three in a row were unsuccessful unfortunately is costing me paper  Angry

I have tried the stock Epson paper profile as well as a custom profile for this printer/paper combo and have also changed the rendering internet and maybe a few other things but the issue remains. Not sure what to try next. I have been using the inkjet republic 3rd party ink system for years with never an issues, and I don't believe the problem is the ink but I've been wrong before.  How the heck does magenta get on a B&W print anyway?

Driver Settings..



Image of print  Although this image looks like it has a cast all over, it's just a bad photo of the print. Real life the grays and tonal range are nice (except for the magenta).
« Last Edit: October 11, 2013, 05:18:54 AM by nbagno » Logged
Terry-M
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« Reply #1 on: October 11, 2013, 07:41:08 AM »

Quote
How the heck does magenta get on a B&W print anyway?
Because you are using coloured inks - has the 3880 got a B&W mode with various grey inks?
Quote
However with both I have made a successful print at least once, the last three in a row were unsuccessful
That seems to indicate blocked nozzles, I suggest you do a check & clean.
Terry
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Lurcherjohn
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« Reply #2 on: October 11, 2013, 10:44:03 AM »

I can see on your driver picture you have 4 different blacks, matte, photo, light and light light.
The drivers seem to add some colour even if you chose greyscale.
My Canon has only 5 inks altogether and I had a similar caste on my black and white photos. There were no blocked nozzles and paper and ink were as usual.
I usually make a new profile with Profile Prism when I fill my CISS system but I made a fresh profile with Profile Prism but the caste was still there.
I solved it by editing my (new) Profile Prism profile, and subtracting 4 units of red. My colour pictures also improved their colour.
I don't understand how the colour can change when inks/printer/paper are the same but it does.
Perhaps your custom profile people can edit your profile if you send the same b&w picture to them as evidence.
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Terry-M
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« Reply #3 on: October 11, 2013, 11:11:07 AM »

Quote
has the 3880 got a B&W mode with various grey inks?
I see now from your screen shot you are using The Advanced B&W mode but why is "Custom" set? I don't know much about your driver but with B&W mode set I would think "automatic" would be needed? Hopefully someone else with this printer will comment.
Also, how is QU set for colour management; again I would think, let driver manage colour was appropriate.
You mentioned using a colour profile, is this relevant when set to the B&W mode?
Terry
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Mack
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« Reply #4 on: October 11, 2013, 04:16:47 PM »

If you are using 3rd party inks in your 3800 there is a chance that the coloration of the ink dyes are different.  I went through that stuff with the 3880 with burple shadows (Search on here for that.).  Someone suggested squeezing a drop of the Matte Black ink into some water (Like you are using.) and see what color it actually is.  Chances are is is some purple color.  I switched ink tanks in a Canon 9000 II as well as the 3880 I have and had a bad shift there too.

Actually, my stuff goes from a yellow to a bluish/purple tint on a 21-step B&W gray scale using the three grades of black (Either Matte Black or Photo Black is selected as the third darker black depending on paper selected.).  Some papers bluish optical brighteners mess up final results too.  I started out with Spyder 3, Profile Prism (Don't trust my HP scanner at all for color!), then a "ColorMunki Photo" (I wanted hard RGB numbers and wasn't trusting my eyes, and the "CM Photo" is sort of fun to use too.).  Later found some paper's OB to have an issue with it, so I sprang for the "i1 Photo Pro 2" unit which negates that problem with UV.

However, you can alter it with a "Curves filter" in Qimage Ulitmate.  I did some work and set up a curve that neutralizes the color casts, just you need to stay in the Color and not Advanced B&W of the Epson Driver window to pull it off.  Most of it is under this link here on "Linearization": http://ddisoftware.com/tech/qimage-ultimate/qtr-linearisation-data-translated-to-a-qimage-print-filter/msg14772/#msg14772

It takes some time to dig through it all, but you can zero out the color casts and clean up the shadow detail and tonal range too. You can even tailor it too got sepia or selenium if you try.  Qimage, imho, has far better sharpening than I got using the QTR RIP software which seems to have failed there.  The QTR forum now has the Mac guys having issues with the software and errors in OS 10.7+.  The Windows GUI coder guy jumped ship it seems as the Windows one was written back for OS prior to Windows 7.  It's old and not much the author, Ray Harrington, can do about it for Windows.).

Good luck!


Mack
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nbagno
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« Reply #5 on: October 11, 2013, 05:47:47 PM »

Quote
How the heck does magenta get on a B&W print anyway?
Because you are using coloured inks - has the 3880 got a B&W mode with various grey inks?
Quote
However with both I have made a successful print at least once, the last three in a row were unsuccessful
That seems to indicate blocked nozzles, I suggest you do a check & clean.
Terry

I check before the start of each print run, no issues with blocked nozzles. 
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nbagno
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« Reply #6 on: October 12, 2013, 05:48:54 PM »

Quote
has the 3880 got a B&W mode with various grey inks?
I see now from your screen shot you are using The Advanced B&W mode but why is "Custom" set? I don't know much about your driver but with B&W mode set I would think "automatic" would be needed? Hopefully someone else with this printer will comment.
Also, how is QU set for colour management; again I would think, let driver manage colour was appropriate.
You mentioned using a colour profile, is this relevant when set to the B&W mode?
Terry

Thanks for all of the feedback. I have it on custom mode because I set the color correction in the driver to darker. I typically like how that looks. Darker is magnifying the problem in this case. Setting back to automatic almost takes care of the magenta cast, but there is still a tiny bit there. I'll just use this as a learning opportunity and figure out what's going on.  By the way, I though once I started inkjet printing that I would be printing less than I do in the darkroom, not the case. I think I use more paper with inkjet than I ever did in the darkroom.

Cheers
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Mack
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« Reply #7 on: October 12, 2013, 07:54:08 PM »

Quote
has the 3880 got a B&W mode with various grey inks?
I see now from your screen shot you are using The Advanced B&W mode but why is "Custom" set? I don't know much about your driver but with B&W mode set I would think "automatic" would be needed? Hopefully someone else with this printer will comment.
Also, how is QU set for colour management; again I would think, let driver manage colour was appropriate.
You mentioned using a colour profile, is this relevant when set to the B&W mode?
Terry

Thanks for all of the feedback. I have it on custom mode because I set the color correction in the driver to darker. I typically like how that looks. Darker is magnifying the problem in this case. Setting back to automatic almost takes care of the magenta cast, but there is still a tiny bit there. I'll just use this as a learning opportunity and figure out what's going on.  By the way, I though once I started inkjet printing that I would be printing less than I do in the darkroom, not the case. I think I use more paper with inkjet than I ever did in the darkroom.

Cheers

Fwiw, that's what I was doing by trying to get a blacker black, i.e. move the printer driver to a darker percentage within the Epson printer software.  Only problem is that is messes up profiles badly for some reason doing that.  Shadows get very blocked up too and you lose a lot of detail in there too.

Yeah, the black goes much darker and richer, but so do the shadows and colors within them too.  Bad crossover from a yellow highlights to a burple appearing around step 8-10 of the 21 step chart, and on up to around step 18 where I saw it still purple until I got to the maximum black (or L value in the x-rite devices).  On one brand of paper, it didn't go burple, but a chocolate brown in the shadows.

I wrote to x-rite since I use their profile tools and they said much the same, "You can't get a decent profile by setting the control to a darker percentage."  The only way you can is to mess with the curves like I do and get a linear profile curve applied after you hit your best black using the color percentage density.  You have to be able to measure your 21 steps though with something (ColorMunki Photo or i1 Photo spectrometer head) to see how it works in the spreadsheet linearization curve tool though.

Once you get it linear (Shadows holding detail, and the whites not being darker up with the more ink applied.), you can apply a bit of corrective color within the step range where you see the burple cast using the Curve tab in Qimage to negate it.  Nice rich blacks and whatever neutral or color tone you want.  You can apply maybe 20-30% Darker in the Epson driver prior to going through it all though to maximize the blacks.

It works, just a big pain to go through it all for each printer and paper.  Sort of a take-off on the QTR RIP software if you work through it a few times, just that that software is too soft for me in sharpness, and it throws out a lot of Error codes both.


Mack
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nbagno
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« Reply #8 on: October 13, 2013, 04:59:17 AM »

Thanks Mac,

I was able to neutralize the issue by going back in to the printer drive custom mode and moving the horz to -5. Looks like that got rid of the rest of the magenta.  Although I send my paper targets off to a service to get profiled I have been thinking of getting an I1 photo pro 2 and doing it my self but the cost has kept me from buying one. Oh, I had to look up burple in the urban dictionary :-)



Thanks,

Ned
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nbagno
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« Reply #9 on: October 13, 2013, 05:03:35 AM »

Well actually, I just zeroed it out and it still looks good. Seems setting the color setting to normal instead of dark was the best solution for me.
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