Stripes on digital negatives

I am making digital negatives for Palladium Printing - and am running into a problem on which I am stuck.

Below are the print and 2 different negatives. seems like it actually reproduces multiple times - not exactly, but close

- Epson P800
- Pictorico Ultra
- Unfortunately I have reproduced this many times
- the negative is actually Printed in yellow 'R255, G210' this is grayscale so the effect is visible
- I have cleaned heads and vertically aligned
- Changed the drying times and the platen gap and paper width - but willing to hear an alternative

I am worried that the printer is flawed at this point.

Normal prints are totally fine

Thoughts?

Are these perpendicular to the carriage movement - i.e. which way the negative was printed?

Welcome to Photrio, by the way.

:Niranjan.

Have you tried a different brand substrate? It could be an issue with the Pictorico.

If that negative was produced by scanning film, I’d consider the scanner as the culprit: check and make sure those artifacts are not in the digital scan.

Thank you for the responses and the welcome!

- This picture was taken with a digital camera (GFX100s) and shows no issues when printed 'normally' on luster/matte/washi
- I am seeing this consistently across many pictures (to the great loss of a lot of Palladium :-( )
- The negative is printed 'vertically' - the stripes are perpendicular (in the opposite direction of the print head path) - which seems kind of amazing
- I inverted the negative on the flatbed to the same result to eliminate the possibility it was the scanner
- I originally thought the stripes came from the UV lights but eliminated the stripes coming from the UV lights and coating procedure through a bunch of techniques like rotating the images when printing/coating differently/etc... so I am 'pretty sure' its the negative.

see the images below

- I am getting this on 2 different substrates
- it seems to occur or be obvious in the high key areas - perhaps the way platinum
- on the negative - it is VERY hard/impossible to see it with the naked eye - which is one reason I eliminated many other things first
- If it is indeed in the high key area - it is the dark part of the negative
- one thought was that the negative material was not absorbing the ink symmetrically or there were drying/smudging issues. I increased the pause between print head passes to the maximum to no avail
- it seems too 'patterned' to be a smudging thing
- I thought the substrate might be rippling - so attached it to a backing material
- also tried different colors

here are 2 different images as I mention above

One has lots of high key areas - one more low key. You can clearly see the 'stripes' in the high key. its not clear they exist in the low key image (I have been staring at it) or if they disappear because of the way platinum works. it does seem like it only happens in the 'thicker' part of the negative

Could be the paper carrying rolls of the printer.

Can you send the file to someone like Fromex and have it printed? That would tell you whether it's your printer or not.

The reason I asked about the print direction is the possibility that this could be pizza wheels, But on a second thought, they tend to be very sharp and I don't think they are placed that close together.

The other possibility I can think of is the horizontal head alignment. I know you said you did the vertical alignment - probably the printer does alignment only in that direction - some of the old models do both horizontal and vertical alignments - my decade old HP B9180 does that, but my Epson P400 does not. I remember one of the first inkjet printer I had (dye-based, 1280?) had both directions. I guess Epson figured their horizontal direction does not go out of alignment in these new printers. I am not sure if your P800 has horizontal alignment capability, that would be something to look into.

Additional thing that might play a role - are you printing at high speed, by any chance? If so uncheck that option, that will disable the bi-directional printing so it prints only in one direction. It is slower but gives a better output, Slowing down also helps with pizza wheels if any.

Apologies if you have considered all of these issues. Hope you can fix this somehow. Those are nice images.

:Niranjan.