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General Forge Forums => Independent Publishing => Topic started by: Seamus on May 18, 2011, 07:34:23 AM

Title: Ink Density Problem for Lightning Source
Post by: Seamus on May 18, 2011, 07:34:23 AM
Hello,

I have a problem with one of our covers which will be printed using lightning source. They changed their total ink coverage (also heard this called ink density) to 240%. I just checked a cover I am sending out and it the whole thing pretty much lights up when I check it in the separation preview for anything over 240. I can easily fix my background swatches that I created. But I am working with an image an artist submitted long ago. The file is in CMYK (though he also did send an RBG), and I am wondering if anyone knows how I can fix this using INdesign. If it can't be fixed in INdesign are there other programs out there (preferably free ones) that can fix this issue---we can't afford Photoshop at the moment.
Title: Re: Ink Density Problem for Lightning Source
Post by: Vulpinoid on May 18, 2011, 08:08:12 AM
Without knowing the previous ink density (before the upgrade to 240%) I'm not sure about the best way to assist in this...

...but that said, I do have a decent amount of experience in image generation, digital image manipulation and various printing methods (digital, offset, even lithography). Most desktop publishing programs from the past few years have crude image manipulation tools in them. I know that my recent versions of Microsoft Word (2000, 2003, 2007, 2010) even have the ability to change brightness and contrast in images.

I'd be very surprised if you couldn't do some minor adjustments to brightness and contrast, and this should account for changes in ink density (and even ink type or printing process).

It's a simple and fairy crude solution, but it should work for most situations. If you want different advice, offer a response and I'll try to give an alternate soution that shouldn't cost too much.   
Title: Re: Ink Density Problem for Lightning Source
Post by: Seamus on May 18, 2011, 09:10:18 AM
Quote from: Vulpinoid on May 18, 2011, 08:08:12 AM
Without knowing the previous ink density (before the upgrade to 240%) I'm not sure about the best way to assist in this...

The image I am working with is at about 310% ink density.

Quote...but that said, I do have a decent amount of experience in image generation, digital image manipulation and various printing methods (digital, offset, even lithography). Most desktop publishing programs from the past few years have crude image manipulation tools in them. I know that my recent versions of Microsoft Word (2000, 2003, 2007, 2010) even have the ability to change brightness and contrast in images.

I suppose it is worth a try in word (I've used power point to change images from color to black and white). However it is the cover art, so I would be concerned about the quality of the image being altered.

QuoteI'd be very surprised if you couldn't do some minor adjustments to brightness and contrast, and this should account for changes in ink density (and even ink type or printing process).

If it boils down to adjusting brightness and contrast, maybe it is an easier thing to achieve than I thought. I guess my concern then would be potential pitfalls. The image is a PSD file, CMYK, one layer. In order to change it, I think I'd have to open it up in another program and save it as a different type of file (correct me if I am wrong). I wouldn't want to do anything that makes it look bad or produces unexpected results.

QuoteIt's a simple and fairy crude solution, but it should work for most situations. If you want different advice, offer a response and I'll try to give an alternate soution that shouldn't cost too much.   

Thanks for the response, I will certainly try this and see how it goes. But other advice is definitely welcome. I have a small program called Draw Plus SE. If anyone knows whether that might be handy in this situation, I could use advice on that.
Title: Re: Ink Density Problem for Lightning Source
Post by: Christoph Boeckle on May 19, 2011, 04:25:44 AM
Hello

I have no idea about the technical aspects you are talking about, but as far as software goes, one that is both powerful and free is GIMP (http://www.gimp.org). It handles .psd files. For optimal handling of CMYK, you might have to install a plugin (http://cue.yellowmagic.info/softwares/separate-plus/index.html).
Title: Re: Ink Density Problem for Lightning Source
Post by: Eero Tuovinen on May 19, 2011, 10:56:25 AM
GIMP is a good program except for the lack of native CMYK support. Are you trying to maintain a CMYK workflow, or do you mind if the material is converted to RGB and then back to CMYK? I cannot speak to the integrity of the GIMP CMYK handling, it's entirely possible that it's not up to professional standards. On the other hand, if you know that the image has already been RGB at some point in the workflow, then converting it temporarily is probably not going to hurt the colour scheme in a significant way.

Regarding the actual problem, it's pretty interesting... the ideal approach would be to use a dedicated graphics program like Photoshop or GIMP to reduce the ink levels, but then you'll need to make your own calls as to whether to reduce the peaks (losing contrast in the darker parts of the art), or whether to reduce ink proportionally (lightening the entire image). Not impossible, but requires knowing what you're doing to your image, and the best outcome will probably be some sort of compromise between those options (to be specific, the best compromise is probably one that keeps the main content of the art deeply inked without losing anything important in the dark places). The other option would be to set up the PDF distiller to reduce the inks automatically, but then you don't know what exactly it is doing (or at least I don't) to the image to achieve that goal.

From what you describe it seems that pretty much your entire piece is over the ink density limit (not too surprising, considering - that's a pretty low limit for book printing), which would seem to indicate that a proportional increase of brightness over the entire image is probably the way to go, or at least the most important bit here. Considering your situation, I would probably send the image to somebody with Photoshop to fix - this would be easier than learning GIMP, and the image is already in Photoshop format. Depending on the complexity of the image this is unlikely to take more than a few minutes for somebody who knows what they're doing, and it's also the method least likely to cause unwanted changes in the print outcome.
Title: Re: Ink Density Problem for Lightning Source
Post by: Seamus on May 19, 2011, 03:49:03 PM
Thanks everyone for the helpful feedback. It turns out the artist was more than willing to adjust the ink levels for me (which is probably best since I don't want to mess with his image too much). But still I will need to figure out a solution for this in the future so I am looking into everything people have suggested.

One question about GIMP. On my previous computer I downloaded it no problem and ran it. On my new computer (which really isn't any different from my previous one in terms of OS or anything) I couldn't get it launched once I downloaded it. Has anyone run into a similar issue with GIMP?