File formats: Avoid file formats like PICT, GIF or BMP which were never meant for design purposes.
Highlight and shadow dots:
The clearest point in grayscale images should not consist of pure white but should have at least a 2% dot in it. Acceptable exceptions are headlights of cars or specular highlights (small light reflexions on a shiny surface) for which it is no problem if they are “blown out”.
The darkest area of the images also shouldn’t consist of pure black. For 150 or 175 line screens, it is customary to use a 95 percent gray for the shadow dots. For newspaper printing, a 5 percent highlight dot and 80 percent shadow dot is not uncommon.
QuarkXPress and TIFF: When placing TIFF images in QuarkXPress (Mac or PC) make sure to never have the background color of the picture box set to “none”. This avoids problems with staircasing (so-called jaggies) at the edges of the image.
Resolution: Make sure images have the correct size and resolution while scanning them. The final resolution of black and white pictures should be (screen ruling x scale x 2). The “2” is a quality factor that can vary between 1.6 and 2.5 depending on your quality needs and the subject of the image. So if you scan a photograph and want to enlarge it 300 percent in the layout application and your publication is printed at 85 lpi, the image should be scanned at (85 x 3 x 2) or 510 dpi.
Size: Never enlarge images more than 20 percent in your layout application. It will reduce the resolution of the images and lead to an effect called staircasing. Reducing images too much will lead to a loss in sharpness and contrast.
Color images
File format: Avoid PICT, WMF or BMP images. The layout application may support these formats but their proper conversion to PostScript or PDF data is never guaranteed.
QuarkXPress and TIFF: When placing TIFF images in QuarkXPress (Mac or PC) make sure to never have the background color of the picture box set to “none”. The image below shows what can happen if the background is set to ‘none’: either there is staircasing (jagged edges) at the edges of the image or white areas within the image simply vanish.
Resolution: Make sure images have the correct size and resolution while scanning them. The final resolution of colour pictures should be (screenruling x scale x 2). The “2” is a quality factor that can vary between 1.5 and 2.5 depending on your quality needs and the subject of the image. So if you scan a photograph and want to enlarge it 300 percent in the layout application and your publication is printed at 150 lpi, the image should be scanned at (150 x 3 x 2) or 900 dpi.
Size: Never enlarge or reduce images more than 20 percent in your layout application. Enlarging them will lead to pixelization and staircasing. Reducing them too much will lead to a loss in sharpness and contrast.
Colorspace: Not all workflows can handle RGB or indexed images properly. Check with your trade shop or printer to see whether they support non-CMYK color modes.
It appears to me that this website doesnt download on a Motorola Droid. Are other folks getting the exact same problem? I enjoy this website and dont want to have to miss it when Im away from my computer.
We’ve just produced a handbook for designers. It answers a lot of the questions here. We’ve included printed examples of things like: different rich blacks, trapping, overprinting, line weight limits, point size limits with different colours and more.
Found you by pure chance and good luck! Love the info, easy to read, understand, interesting and with a sense of humour which you really need in this industry sometimes ha ha.
Great stuff, thanks.
Are you on facebook, twitter or linkedin at all?
Thank you for the effort you have put into this site. I was looking for well-organized stuff to pass onto our prepress operators so that they would send me good PDF files to run through our digital presses. For example, a 100-page file sent to me would not work. They made several attempts to improve the file until one did work, but took an hour to rip. In frustration, I took the PDF file, optimized it (reducing size from 103MB to 19MB), ripped it in 10 minutes, and produced an acceptable proof. In the past week, I estimate I have wasted 10 hours in a 60-hour week because of bad PDFs.
I found your blog on google and read a few of your other posts. I just added you to my Google News Reader. Keep up the good work. Look forward to reading more from you in the future.
I have had and encountered remarkably few problems with transparency myself. That is probably a coincidence as it is a favorite topic in many prepress discussions.
Two of the suggestions which I see pop up regulary:
– As a general rule, make sure that text in InDesign is all put in a separate layer which is the topmost layer.
– Don’t mix different color models when using transparency. For example: don’t put text that is CMYK (or just K) with a drop shadow on top of a background which is defined using spot colors. A lot of problems can be avoided by correctly defining colors in the InDesign Ink Manager. You can use spot colors in InDesign but if they are going to be printed in CMYK, define the colors as being separated right from the start. I have gotten around a few issues with white rectangles appearing in the background by redefining the colors properly in an InDesign job. Maybe that is what your printer does as well?
One recurring issue I have is with drop shadows, particularly in InDesign which look fine on lasers, but when run to digitals often ‘block out’ the vignette area as a flat colour. Printers usually manage to solve the problem, but are not able to supply me with an explanation as to the cause.
good post
It appears to me that this website doesnt download on a Motorola Droid. Are other folks getting the exact same problem? I enjoy this website and dont want to have to miss it when Im away from my computer.
Hi guys,
We’ve just produced a handbook for designers. It answers a lot of the questions here. We’ve included printed examples of things like: different rich blacks, trapping, overprinting, line weight limits, point size limits with different colours and more.
I just thought it might be useful to people here. Do check it out at: http://www.printhandbook.com
Andy
Found you by pure chance and good luck! Love the info, easy to read, understand, interesting and with a sense of humour which you really need in this industry sometimes ha ha.
Great stuff, thanks.
Are you on facebook, twitter or linkedin at all?
very nice and useable information. thx
Thank you for the effort you have put into this site. I was looking for well-organized stuff to pass onto our prepress operators so that they would send me good PDF files to run through our digital presses. For example, a 100-page file sent to me would not work. They made several attempts to improve the file until one did work, but took an hour to rip. In frustration, I took the PDF file, optimized it (reducing size from 103MB to 19MB), ripped it in 10 minutes, and produced an acceptable proof. In the past week, I estimate I have wasted 10 hours in a 60-hour week because of bad PDFs.
I found your blog on google and read a few of your other posts. I just added you to my Google News Reader. Keep up the good work. Look forward to reading more from you in the future.
Drop shadows = transparency
I have had and encountered remarkably few problems with transparency myself. That is probably a coincidence as it is a favorite topic in many prepress discussions.
Two of the suggestions which I see pop up regulary:
– As a general rule, make sure that text in InDesign is all put in a separate layer which is the topmost layer.
– Don’t mix different color models when using transparency. For example: don’t put text that is CMYK (or just K) with a drop shadow on top of a background which is defined using spot colors. A lot of problems can be avoided by correctly defining colors in the InDesign Ink Manager. You can use spot colors in InDesign but if they are going to be printed in CMYK, define the colors as being separated right from the start. I have gotten around a few issues with white rectangles appearing in the background by redefining the colors properly in an InDesign job. Maybe that is what your printer does as well?
Great site – really worthwhile and useful!
One recurring issue I have is with drop shadows, particularly in InDesign which look fine on lasers, but when run to digitals often ‘block out’ the vignette area as a flat colour. Printers usually manage to solve the problem, but are not able to supply me with an explanation as to the cause.
with thanks