Mike Chaney's Tech Corner

I am printing large canvas prints and need a way to compensate for the normal one way shrinkage that occurs.  This is easy to do outside of Qimage by stretching (slightly) the vertical length to compensate for shrinkage.  I usually use 1.01xxx depending on whether I am in portrait or landscape.  I make sure that constrain proportions is turned off and the end result turns out perfectly.  I thought I could maybe accomplish this in Qimage by factoring in my slight stretch when I designate a specific size for my print.  However it doesn't apply my slight stretch.  I wanted to eliminate any interpolation other than with Qimage. I realize I could apply this tiny stretch in PS but that results in a double (even though very tiny) interpolation.  Is there a way to do this in Qimage?

Victor

Victor

This is normally done in the printer driver using the 'Paper Feed Adjustment' setting.

Brian

I feel very ignorant right now..... I have never thought of using that adjustment for my 9900.  I have also not seen any posts regarding that as a fix for normal canvas shrinkage.... but that doesn't mean that it isn't the proper solution. 

Thanks for the post.....

Victor

Brian,

Paper feed adjustment is used to compensate for any/some banding issues.  There is no adjustment that I can see to accomplish what I want.  I have to make up almost 1/4 inch to have the print turn out to my specified dimension..... that is why compensation/resizing in one direction is used.  The question remains..... can Qimage accomplish what I want?

Victor

Qimage will not distort prints if that's what you are looking for.  I've always thought that fixing canvas shrinkage is best done via the reverse of how it happened in the first place: by proper mounting/stretching techniques via the stretcher bars.  The canvas doesn't actually shrink.  It is stretched slightly as it is being printed (due to tension of the rollers, etc.) and after it exits the printer, it relaxes.  That's why it only stretches (appreciably) in one direction: the length.  So if you stretch it with the stretcher bars to remove the shrinkage, you're actually putting the canvas back into the state it was in when it was printed upon and I believe the best quality will be obtained that way.

BTW, I have heard of people using the "paper feed adjustment" to compensate for shrinkage: it's not just for banding.  I've never tried it but I've found people who swear by it, and given how/why the shrinkage is occurring, I can see how that would work.

Mike

Victor

There are suggested settings here (for the 9880 but should apply to the 9900):

http://www.premierart.info/pm_driver_settings_canvas.php (http://www.premierart.info/pm_driver_settings_canvas.php)

Brian

For each of my Photoshop Canvas Wrap Actions I have a step at the end for a one dimensional stretch function to compensate possible canvas shrink. As not all canvas qualities show the same shrink it is easier to have it done at the wrapping stage than changing media feed on the printer driver or in a RIP. Not all drivers or RIPs have that last feature. It is also not entirely clear when the shrink happens, when the canvas unrolls from the core or when it dries after the print.


met vriendelijke groeten, Ernst

New; 250+ Spectral plots soon extended with the Canon US catalog:

http://www.pigment-print.com/spectralplots/spectrumviz_1.htm

Thank you Brian, Mike and Ernst.  I really appreciate all responses.  I can easily live with allowing PS to perform this one way slight distort, but will try the other recommendations.  If I were doing gallery wraps this wouldn't be such an issue but I am doing museum wraps which means that dimensions have to be on the money..... or making stretcher bars to fit.  I initially started out using IT stretchIT bars and then decided that I could make those myself which makes it easier for odd/custom sizes. 

Thanks for taking the time to respond.....

Victor