Automatic re-sample and reinsert images in incoming pdf to avoid moire on output

[effeegee]

Any ideas on this anyone? Digital printing of a (mono) pdf file produces moire in coarse screened images on output resulting from 'too similar rulings'. Is there a tool/workflow which can pre-flight files to identify images and automatically re-sample and re-insert in the same size and position? Blurring of the entire file is not acceptable because of the impact on text and ideograms.

Is this Pitstop (or similar) territory? What would image processing routine can be scripted to achieve this? (Photoshop is too crude and slow.)

[Greg_Firestone]

Hi effeegee,

So it's a grayscale PDF which contains a screened image. Was the image scanned or just pulled from a 1-bit tiff? What is the original resolution and what resolution do you want?

There are applications which can automatically do what you need. How many files do you need to do this to? It will help determine which solution would be most cost-effective for your needs.

Regards,
Greg

[effeegee]

Hi effeegee,

So it's a grayscale PDF which contains a screened image. Was the image scanned or just pulled from a 1-bit tiff? What is the original resolution and what resolution do you want?

There are applications which can automatically do what you need. How many files do you need to do this to? It will help determine which solution would be most cost-effective for your needs.

Regards,
Greg

Greg

My understanding is limited soon it will be more appropriate to put others on line but after a quick look at PreMedia web site and there are aspects to explore. The whole file is a 1-bit TIFF - a mono newspaper page for international digital reproduction at a reduced size. The clash of rulings does not require a specific resolution shift so much as a change for all and any pre-screened output such that this preclude moire. Speed of turn round and automation to suit a daily production is the requirement.

Thanks for your response in advance

[Greg_Firestone]

Greg

My understanding is limited soon it will be more appropriate to put others on line but after a quick look at PreMedia web site and there are aspects to explore. The whole file is a 1-bit TIFF - a mono newspaper page for international digital reproduction at a reduced size. The clash of rulings does not require a specific resolution shift so much as a change for all and any pre-screened output such that this preclude moire. Speed of turn round and automation to suit a daily production is the requirement.

Thanks for your response in advance

Hi effeegee,

If the entire page is a screened 1-bit TIFF in a PDF wrapper, I don't know of any apps off the top of my head which can automatically modify what was originally image content and not touch what was originally text and vector. Automated software won't be able to distinguish what is image data since the entire document is essentially one large image. I assume there's not an option in the workflow to output unscreened 1-bit tiffs...

There are manual tools which can do this, which are probably better and faster than Photoshop. I can't speak for Pitstop specifically, but I know that with OneVision Speedflow Edit you can copy and paste the image in place, create a clipping path around the image, adjust the resolution, and then automatically remove the cropped out data when saving.

Regards,
Greg

[abc]

Your best bet if possible would be to discuss the issue with your supplier and see if you can get a normal object based pdf from them, this is a pretty standard format now for newspapers so unless there is a good technical reason there shouldn't be a problem

[pacart]

So is assume that because you already have the image screened, you get the moire because the digital machine is screening it again when it prints it? If this is the case i suggest maybe setting your digital machine to print lines rather than dots and see if this will fix this issue, the only other way to get rid of the screening is to descreen which will blur and you said that was not acceptable.

[james.bredenhof]

Prinergy has a Copydot JTP which can do moire-free resample of incoming 1-bit data to the effective resolution of your output.
PDF with 2540 dpi 1-bit screened data in, PDF with 2400 dpi 1-bit screened data out, for example. Very stable/proven technology.