Looking for Advice - Printed Image Corruption

[TheGimp]

Hi Folks,

Having a problem with printing images.
In the attached photo, you can see a scanned section of a print. The original was printed on a laser printer, a Canon iRC2620n. The problem is the blocky grey 'rash' on areas of the images. The rash only appears on bitmap images, not on text or vector graphics. The images are jpegs from a digital compact.
Does anybody know what causes this, and how I can avoid it in future?
All advice appreciated.
Cheers,
Stuart.

 

[Al Ferrari]

What does Canon have to say about it?

Al

 

[twitch5253]

what is the resolution of the images? are they being placed into a document?
and what do you have for image quality settings at the printer?

 

[TheGimp]

Haven't asked Canon yet.
The resolution I'm not sure about. They started as 72dpi from the camera (modern Sony Cybershot), but will have changed as the attached jpeg there was created in CorelDRAW X5 (When I shrink images in Cdraw, the dpi appears to shoot up). The jpeg was made from a CorelDRAW file using either Export or Publish to PDF (with no downsampling). The settings are definitley not turned down on the Canon, as we use it sucessfully for many other prints. It's just some pictures have that rash, and I don't know why.

 

[airyk]

the image you posted is rather small and hard to get a good look at. Before printing, do the images look okay in Photoshop?

 

[SteveL]

It looks like posteurisation due to low resolution and JPG compression.
Use a higher resolution image, and if you need to use JPG's, set the option to Maximum Quality when making the JPG.
72dpi is too low a resolution to use when designing for digital print.

 

[cmitchprint]

It looks like posteurisation due to low resolution and JPG compression.
Use a higher resolution image, and if you need to use JPG's, set the option to Maximum Quality when making the JPG.
72dpi is too low a resolution to use when designing for digital print.

72 DPI is too low for most any printing. If it's not at least 300 DPI, we don't even use it.

 

[TheGimp]

Thanks folks. Did not discover the cause, but printing from PDF instead of CorelDRAW solved it.
Now dealing with blistered print.
Grrr....

 

[Mark Flanders]

This is a corrupted image, not a resolution issue. (the 72 dpi thing is misleading because the Sony Cybershot image was probably 38" wide @ 72dpi, so changing it to 300 provides a good usable image.) The solution of using Acrobat to reprocess the file gives the clue...which is "Don't use Corel Draw to place or export images." (unless you have no better choice, I guess) it's a vector drawing program, not an image or layout program. (an overpowered, clunky drawing program at that.) It rewrote the raster data and did a messy job of it. Back up and rewrite that data from a more solid source in the future. I hate to say it, but use Publisher if you don't have Indesign or Photoshop. It's at least designed to do page layout. Thanks for posting!

 

[DCGWest]

Please make sure if your scanner is away from a strong magnetic material as it also causes scanning problems.