Vertical "ripples" in print


#1

Here is the setup:

I printed a 15H x 30V print on Canson Rag Photographique 310. The inkset is SPED on a 3800. The image was printed from QTPrint with no color management at 100% resolution (i.e. no enlargement or reduction made by QTPrint). The profile used was “7890-9890-CansonRagPhoto” from QTR. The image is primarily dark tones (L = 5 to 50).

Here is the problem:

When I look at the print the paper has vertical “ripples” approximately 3/4" wide running the entire length of the print. One ripple seems to be raised while the next ripple seems to be lowered. The ripples are perfectly parallel. You can only see the ripples when you look perpendicular to them. This is not micro-banding that occurs at the leading / trailing edge of the print under certain printing conditions. I printed the image three times and each time was the same. It almost feels as if due to the nature of mostly dark (e.g. MK, Y, LM, and LK ink if looking at the .quad file using QTR-CurveView) that the paper absorbed the ink in a way to cause the ripples. It has now been 24 hours since the proofs were made and the ripples are still there.

The paper was cut from a new roll and flattened for several days before printing. Enclosed is a photo of the back of one of the proof prints and the vertical banding is clearly evident.

Any ideas? Or questions?


thanks!


#2

This is caused by the printer platen (the ribbed area right under the print-head).

This happens with all epson printers and plagued me when I was a young printmaker in Chicago.

Solution that a devised: right after print, roll print inwards perpendicular to the ribbing between glassine and let dry overnight. This flattens the ribs out during dry-down.

An old-school darkroom hot-press at 160 degrees for a few minutes also works.

best,
Walker


#3

Walker,

Thanks for your information and taking the time to answer; I appreciate it! Your answer makes perfect sense since the ripples were so uniform in nature. Here is what I also discovered. I also think that the humidity in my studio is below the recommendation by Canson and Epson (It is winter and I live in a very dry part of the southwest US.). And the fact that the image is very, very dark (taking a lot of MK ink). Your solution for using a hot press is also what I tried. I humidified the back of the paper first for a few minutes (using a standard room humidifier and gently moving the paper back and forth over the steam; only on the non-printed side. I did this not to wet the paper but just to loosen the fibers a little.) After that I placed it in a hot press at 180 degrees for about 8 minutes. Most of the ripples were removed. I will try your suggestion as well next time.