Increase CGO to eliminate bronzing

In some test prints on Ilford Gold Fiber Silk, I’m getting some gloss differential where the quarter tones transition into the highlights. RGB values around 215. It reminds me of printing on my 9800 with P2 inks where the IGFS and other similar papers (Canson Baryta, HFA Photo Silk Baryta) needed 2 or 3 passes with GO to eliminate bronzing. It’s not as severe as a P2 print with the IGFS or its clones, but it’s there.

How does one increase the CGO applied? It was straightforward to modify the GO curves, not sure with the PiezoPro curves.

I have some much higher GCO curves in the lab, will send you the LLK channel numbers.

 

best,

Walker

Then you can use blender to tune between the two curves to modify the GCO to your heart’s content.

Yes, some heavy baryta papers go wonky when interacting with GCO (or GO).

-Walker

I am having a similar problem with Canson Barya 310 and need some way to increase GCO .

Thanks

I ended up increasing the GCO values by 5%; this solved the problem for me.

Hey John. Here’s the LLK channel for x880 and x900 series printers increased by 10%.

x880: [attachment file=29394]

x900: [attachment file=29395]

Replace your # LLK Curve section in each .quad with this content. (You can open the .quads up in a text editor, I suggest Sublime Text).

Sorry for the delay,

-Walker

x8-LLK.txt.zip (1.21 KB)

x9-LLK.txt.zip (1.18 KB)

1 Like

Thanks.

Prints are beautiful,

Hi Walker.
I hope everything is good. Strange times.
I have the same problem with bronzing. I’m printing on a 9900, on MediaJet Museum Natural Silk.
You can clearly see a matt surface in the darker tones.
I have replaced the LLK Section according to your instructions above and when I open the curve in QTR-CurveView I can see that the LLK curve has changed.
However, when I print I can see absolutely no change in the matt areas. ??

All Best
Johan

Please share a photo of the “matte” areas.

GCO is not exactly built to gloss matte. Also if you are using MK (matte black) ink this will not work.

best regards,
Walker

The paper is glossy and I’m using HDPK ink. I have tried several different paper curves but they are all giving the same result.
I’m starting to think the problem is something else.
I set the printer up last winter and I have been busy doing other stuff since then.
When I look back at the test prints I made back then, the gloss is perfect (on the same paper) , very even in all tones.
Can the gloss solution get old ? Have tried different paper batches and I can also see the problem on Hahnemuhle Fine Art Baryta.
A nossle check looks ok.
I hope you can see what I mean on the photos.

Best Regards
Johan

Here is a print from seven months ago. Same paper.
You can see there is no change in gloss in light or dark areas.

It looks to me like you are printing Matte Black ink. You need to make sure your printer is set to Photo Black

I think you are right. I thought the printer did this automatically.
I have done it manually now and will make a test print ASAP.

Thanks ! I was preparing for another trip to Topsham.

Thank you Walker !

Prints look beautiful now.

Best Regards,
Johan

1 Like