Printed image 'compresses' closer to end of roll

[Mike Guilbault]

I just finished a print job for a client - 10x 8x12" images which I printed two up on a 17" roll of Cold Press Natural. I know I was getting close to the end of the roll so was just printing out two at a time. The first set came out perfect, but it wasn't til I printed the last set that I noticed the image was shorter. I compared the different sets and each progressive set was about 1/8" shorter than the previous until the last one was almost exactly 1/2" shorter - so 11.5" in length rather than 12".   The entire image was printed, but it was just compressed to 11.5"... and then I ran out of paper and waiting for a new roll to arrive.  I tested another pair on some enhanced matte paper and it printed the full 12" length.

I don't recall this ever happening before, although I can't say that I measured any previous print to ensure it's exact size, so my question is, has anyone experienced this 'compressing' of prints near the roll end?  CPN retains a lot of curl and wondering if that has something to do with the feed and if an adjustment on platen pressure should be made.

[dgberg]

Had to delete my post as I just reread and see you were printing just 2 at a time,
Where was the extra white wide border from the short print, at the start or finish of the print?

[hugowolf]

I can't see it being an end of the roll thing, but maybe. Perhaps if the end of the paper is well glued to the core? For most of my rolls, the paper frees itself of the roll at teh end and is basically feeding as a sheet.

There is a way of calibrating the printer for a more exact sizing for specific papers, although I have never used it. I think there is also some tension adjustment parameter in the menu somewhere. Otherwise a strong vacuum setting may counter it?

I have never had the problem that I noticed, but when doing a 15' print, I did notice it was a little short of 15'. The print (on Canson Rag Photographique 310) was to be folded (concertina style) fo form a fold out book, and the 'pages' near the end of the print may have been slightly shorter than the initial 'pages'.

Brian A

[One Frame at a Time]

Maybe with the tighter curl the paper feed is slipping somehow?

[Ernst Dinkla]

Maybe with the tighter curl the paper feed is slipping somehow?

My thoughts too, it is a heavy paper, 340 gsm, and a small roll, 17¨, so I wonder on what printer it was used.
The last windings of Museum Etching, 350 gsm, require more force to pull through in my experience. The last 2 meters I rather decurl a bit and rewind then on top of a new roll.

Met vriendelijke groet, Ernst

http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
December 2014 update, 700+ inkjet media white spectral plots

[howardm]

perhaps the paper is slipping a bit and the rotary encoder attached to the drive mechanixsm is getting bad data.

[Ernst Dinkla]

perhaps the paper is slipping a bit and the rotary encoder attached to the drive mechanixsm is getting bad data.

The nicest feature of the HP Z6100/Z6200 models is that they do an optical measurement for media progress on the paper surface itself, next to an encoder. The technology is not more complex than what an optical mouse has aboard but I guess it is patented for some time to come. The Z3200 etc rely on a rotary encoder only.

Met vriendelijke groet, Ernst

http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
December 2014 update, 700+ inkjet media white spectral plots