Hahnemuhle paper issue

[George Collier]

I have been working with a printer locally to get large prints made from PShop files, Black and White, but from RGB files with a tiny (1 - 2%) amount of Red and Yellow added to the top and bottom of the curve, just to ensure no blue or green.
Working with Hahnemuhle's expert in Chicago, and the printer, we've developed settings and profile, etc so that my iMac 27" display looks very close to the results. He is using a Canon 12color press (4000 series). The results are beautiful, and the slight warm cast is something like my silver prints toned in selenium. The paper is Hahnemühle Fine Art Baryta.
In beginning to run some actual prints, we see very small white "marks" randomly appearing in prints. They look like dust but I think are really where ink is missing, or maybe the emulsion is cracked. You see them in dark areas, but they can be lost (hard to see) in image detail.
We are working with Hahnemuhle's suggestions, mostly about media settings with the printer, but I thought I would pitch the question in case anyone has had experience with this. It is mid winter, cold and dry, even in Richmond, VA, so static could be a factor.
I've attached an image, but note that the iPhone shot tends to exaggerate these marks considerably, but you can see the general look of them here. They are most evident in dark areas, like the bottom of this one.
They are very hard to see in most of the prints but some have one or two, in a dark plain area that would have to be spotted.
Any experiences or thoughts about this? We are about to try another paper.

 

[nmp]

They might be little debris particles made of the coating material that sometimes get on to the paper during manufacturing. If that's the case, try blowing them off prior to printing using a good blast of compressed air. Other than that if it is not happening with other papers, the onus should be on Hahnemuhle to send a new defect-free supply.

:Niranjan.

 

[Lachlan Young]

They look like dust but I think are really where ink is missing

Have you considered that it might be from paper dust that has settled (got stuck by static?) on the paper surface. Vacuum platen printers shift a fair amount of air around & the internal cutter generates a fair bit more dust than you might think - there are also internal air filters in the machine as far as I can recall. I've very very occasionally had a tiny mark or two on Photo Rag in areas of pure black - and equally rarely a speck of something under the emulsion. For what it's worth, I use the Pro 2000.

 

[Sal Santamaura]

Hahnemühle FineArt Baryta Satin (not exactly the same paper you're using, but perhaps close enough) is my primary inkjet printing medium. I run it through a Canon PRO-100. When initially experimenting with numerous paper/printer combinations, I was shown this one by Dick Phillips of view camera fame. Several of his prints included large dark areas. I commented to him that there were "speckles" in those regions.

Upon further examination, I determined that those spots were really small reflections of bright, oblique illumination striking the prints. There's a very fine texture in the paper (at least the Satin version) with "wells," the "walls" of which behave like the mirrored surface of a polished dark automobile finish when lots of black ink is applied. Rotating the print or light source makes them disappear.

You might have an entirely different problem, but it's probably worth checking to see whether what I've described is relevant.

 

[Lachlan Young]

@Sal Santamaura the Chroma Optimiser in the wide format Canons seems to even out the lustre-like surface propensity you describe into something rather smoother without significantly affecting the inherent level of gloss overall - this is certainly the case on HFABS (to use a terrible acronym) - but it will depend on whether the CO is used across the whole image or in default more limited mode. The FA Pearl can have a bit of an odd sheen effect, but it's clearly regular in pattern as opposed to intermittent speckle effects. These papers aren't necessarily coated (or, more importantly, converted) in the same super-clean low-dust environments as silver gelatin (unless you want to pay even more money) - and I get the sense that they toll-coat a significant batch & convert as needed, potentially over many years - and I have had paper from both Canson and Epson that has been a little wonky in size/ edge straightness - the big Canons actually optically measure the paper when they prepare to print & do their best to centre things - it picked up on sub 1mm variance on Photo Rag sheet widths.

 

[George Collier]

Thanks, all, for your comments, I'll forward them to the printer. I didn't mention it but maybe you've assumed that we print from a roll, and we do.
We have considered some of these things.

 

[jtk]

If you're having dust problems the answers include keeping a hood or some kind of fabric sheet over the printer between uses and blowing dust off paper immediately before printing. Sometimes dust lands on paper as it's being cut...before printing....that's a classic problem.

 

[jtk]

Years ago some otherwise excellent inkjet papers were cut into sheets from rolls by dealers who weren't aware of the dust problem created by their cutting process ...but did follow up online with instructions ... brushes and blowers etc.