Horizontal banding when using QTR

[Jarvman]

Hi all, I feel like I'm getting somewhere with calibrating my Epson R2880 for palladium with NA2 contrast now. Made a negative earlier that appears to have printed well. Won't speak too soon as it's still wet though.

Anywho, the one problem with the neg is banding!. Faint light horizontal lines on the neg that are apparent in the print. I have run a nozzle check to see if that's the problem and everything checks out fine. There are no missing areas in the test print. It has been cleaned recently.

I have printed a portion of the negative though Photoshop without applying the curves layed down in QTR. The test is fine, no banding to be seen. I then printed the same portion in QTR with correction curves applied and bang, I see banding again! It therefore leads me to believe that something is going on in QTR that is causing this problem. I've attached a screenshot of my setup. Could anyone give me their ideas on this matter? Would be most appreciated.

Cheers,
Gareth

 

[Herzeleid]

Does banding happen in highlights? or Does it happen close to the edges of the ohp?
I am a newbie to QTR but you might consider using 2 or more inks for low density areas.
http://www.digital-negatives.com/Document Files/Improved QTR printing.pdf

It is just a guess I have no experience with your inkset.

 

[Joe Lipka]

What software are you using when you print your negative? Are you printing directly from photoshop or some other photo editing program? Or are you using a desktop publishing program such as inDesign? I had that problem using inDesign. I was able to solve it by correctly placing the photoshop file into the inDesign document.

 

[Jarvman]

Herzeleid, thanks for the document. Hopefully something in there will help. The banding I'm getting isn't as described there. It's very close together and apparent in all areas of the print, not just in the highlights half an inch a part. Joe, I'm printing through a 3rd party Driver called QTR which tells to the printer how much ink to lay down. Cheers

 

[Davec101]

Can you scan in the print showing the banding, that might help.

 

[Jarvman]

Its very subtle, but its there I assure you!

 

[Herzeleid]

I see some lines but I can't be sure if that is banding or the paper texture,if you can scan some details, it might be helpful for someone with the knowledge of your printer.

BTW there is a yahoo group for QTR. It is quite active you should share your problem there too.

I had weird issues with my negatives linearity and solved it by using different color combinations,
by increasing contribution of weaker inks (it helped my grain problem a lot).

And one more thing, Yahoo QTR group has some profiles, user contributed profiles.
I checked Epson2880 and there is a Pt/Pd profile quite different than yours. Its use of colored inks are different.
You should give it a try, or may be the ink combinations in that profile might solve the banding problem.

 

[Joe Lipka]

The driver is not the issue. My question was what software program are you using to edit your image with? Are you printing directly from photoshop, or are you using a desktop publishing program?

 

[Jarvman]

Cheers Herzelied. I will try the profile provided on the QTR board and see if that works out. I'm inverting my images in Photoshop then saving them ass Tiff to My Documents.

 

[Jarvman]

The R2880 curve is supplied as a text document not a qidf file. I'm not sure how to apply this on windows considering there is no text dialogue like on a Mac. Do I just go through the windows and change the values manually? Cheers

 

[Herzeleid]

If you can see the extension of your files just rename it if not there is a setting under folder options - uncheck hide extensions for known file types. You change .txt to .qdif. Then copy folder or load it through curve tools. If you open a qdif file with text editor, you will see it is plain text format.
Manually entering the values will work too.

 

[Jarvman]

Ive just applied the curve in QTR. It looks very strange. The step wedge Ive printed has a lot of magenta in the shadow values, cyan in the mids and light cyan in the highlights. The guy has named it 'rainbow nega'. Perhaps this explains why. Anyway, the printing of the step wedge still doesn't look too smooth. Some degree of bandiness/grain.
Not too sold on this QTR just yet.

 

[Jarvman]

Plus it only uses four inks. According to the document supplied earlier in this thread 7 inks is the way to go for smooth negatives...

 

[Herzeleid]

My step wedges are very colored too. Magenta shadows cyan and magenta mix in midtones and greenish yellow highlights and black.
Grain is hard to defeat, and to some extent I believe it is up to the transparency material, and somewhat to the print process used.
I get less visible grain in salt prints than cyanotypes.

Banding is strange really I never had problem with banding using QTR, only when I am very very close to the edges of ohp material or if I used too few colors.

There are 4 gray inks in that profile 2 inks copy it from the other inks. Uses 6 inks and I think that is ok. May be you could include the seventh to the tones that show banding.
I have assigned 2 gray inks the rest copies the curves.

 

[Jarvman]

I just find it strange that the negs are so colorized when I was led to believe that QTR adjusted the levels of the black/gray inks to get sufficient UV blocking, with perhaps a small amount of yellow. Will have to give this a blast and see how it works before commenting further really.