tips for printing images w/lots of black

[sesshin]

Whenever I print images with lots of solid black in them with matte ink on my Epson 7800 (2880 dpi), about 1 in every 4 prints gets streaks, smudges and lines through them in the dark parts. I have figured out that these happen while taking the print off of the printer, cutting them and stacking them. If the edges of another piece of paper even so much as barely touches a black area, it leaves a large line that is visible from certain angles.

What can be done about this? I've tried lowering the color density in the print utility, but that seems to affect colors overall instead of just the darks. I've extended the head pass time, let the prints set for 20 minutes without handling them  but that doesn't help at all either.

[framah]

First, don't stack them till the next day... but you might also want to print at 1440 dpi. 2880 is overkill.

you might also want to try a leaf of paper between each sheet large enough that it doesn't allow the prints to touch each other.

[sesshin]

First, don't stack them till the next day...

I routinely print runs of 50-150 at a time, I'm not really sure what other option I have but to stack them. If I just printed a few a day it would take weeks to finish an order and I would fall far behind.

but you might also want to print at 1440 dpi. 2880 is overkill.

I'm going to experiment with this but have had problems with both dpis in the past and have seen banding with certain images at 1440, so have just stuck with 2880 mostly. I'm starting to think black-heavy images should be printed on 1440 regardless though.

you might also want to try a leaf of paper between each sheet large enough that it doesn't allow the prints to touch each other.
[a href=\"index.php?act=findpost&pid=202280\"][{POST_SNAPBACK}][/a]

I've also done this before but cutting 100s of interleaving sheets at a time got to be tiresome, but hey if it helps save some damaged prints it might be worth.

[neil snape]

I would set a hair dryer on high and have a stand hold it pointed at the print as it comes out of the printer. Not a best practices method for color but one that might avoid this nasty problem.

[Ernst Dinkla]

I'm going to experiment with this but have had problems with both dpis in the past and have seen banding with certain images at 1440, so have just stuck with 2880 mostly. I'm starting to think black-heavy images should be printed on 1440 regardless though.

[{POST_SNAPBACK}][/a]

That's what I see more often mentioned. The use of higher resolutions than needed just to overcome banding issues which is either the result of filthy heads, heads wearing out or bad alignment. While it gives slower printing speed and longer drying so not bad for your case at the same time the inkload can be higher depending on the Epson model. That higher ink load doesn't have to deliver a better Dmax though and asks for longer drying times. Most of what I printed in the past on Epsons could be done with 720 dpi and the prints could be stacked without problems.

No mention is made of the paper you use. Matte papers that smudge when taken off the printer isn't something I did experience with any of the Epsons or the HP.
Can the coating actually take that load of ink ? Isn't there another reason like the head being filthy and carrying over that filth to the transport rolls ?

Lines where the matte black surface is touched by the corner of another print shortly after printing or worse by fingernails are just a thing you have to live with and make sure it doesn't happen. Dried prints can get the same marks.

Depending on the size you could get a secondhand silkscreen drying rack (large prints) or possibly an old air dryer belt as used for analogue photo prints. Equipment that became obsolete as a result of the inkjet revolution. I have similar equipment here but it is seldom that I needed it for inkjet printing. Some cheaply coated canvas rolls that dry badly, a backlit film that gets an overdose of ink for saturation will go through my silkscreen drying tunnel, nothing else. There's a hair dryer cap on a carton box to speed up the drying of proofs and targets to get the color fix faster.


Ernst Dinkla

Try: [a href=\"http://groups.yahoo.com/group/Wide_Inkjet_Printers/]http://groups.yahoo.com/group/Wide_Inkjet_Printers/[/url]

[janisr]

...about the line on the print - I have noticed the same problem when printing on sheets - what I did is - increased the canvas size in photoshop, and added one little spot of any color about 3 cm from the end of the photo on the white.. so the line was on the blank part of tehe print.

well it is really stupid, that you have to fool the 10 000 dollar price machine like that (epson 9800) - it should have not have these kind of problems

[Jeff Phillips]

Go into the print driver and increase the "Drying time per Print Head Pass". On a mac with an epson the work flow is:  Photoshop -> Print-> Print-> Paper Configuration-> Move the drying time slider to something that works. A half a second increase is the max.  This solution lets the ink dry before the print heads move over the paper and usually eliminates the banding.  Good luck...