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• • November 13, 2010 at 6:14 am #57723
    Mayoor Chheda

    Member

    I am about to place digital camera images in an Indesign document. The images are shot via 8 MP camera in JPEG format. They are to be placed in graphic frames of approx 3 inches in size (thereby scaling down in size). I wanted to know whether I should first use Photoshop to reduce the size of the images to about 3 inches & the resolution to 300 ppi. Would doing this degrade the image quality. After reducing the size & resolution, should we save in JPEG format or as PSD files. Somehow, I felt that keeping the files at the same size & resolution before placing in ID resulted in a better image when compared to those images which were downsized in Photoshop before placing in ID

  • November 13, 2010 at 10:55 am #57724
    Theunis De Jong

    Member

    Well, yes, yes, and yes. (I think.) The only “no” I'd suggest is on saving as JPEG. [a]

    If you reduce the size of an image in InDesign, you are automatically increasing its resolution. On exporting, InDesign may decide the resolution gets ridiculously high — default is above 450 dpi — and automatically downsample it to its default of 300 dpi. Therefore, it really doesn't matter if you downsample it yourself to 300 dpi, or let ID do it for you.

    Downsampling does “degrade” the image quality, because it needs to throw away actual data. However, if the resolution after downsampling is still sufficiently high for your intended output target (print?), the degradation is not visible at all.

    [a] Given a choice, you're better off saving as PSD. If you save as JPEG — even using the highest possible quality –, its compression introduces artifacts. That kind of artifacts is most visible when using the lowest quality (try it!), and they may very well be invisible at 300 dpi. But if you decide the image doesn't look right, open it again in PS, adjust something and save it again as JPEG, the amount of artifacts increase. Do it a couple of times, and it gets worse every time. PSD uses a lossless compressed format, so it doesn't suffer from this.

  • November 14, 2010 at 6:26 am #57731
    David Blatner

    Keymaster

    I'm going to agree and disagree with Theun. First of all, yes, doing the downsampling in Photoshop first is a good idea. However, it's not true that it doesn't matter whether it's done in Photoshop vs. InDesign! You can get a much better quality in Photoshop because ID's downsampling (at print or pdf-export time) is very limited and not very smart. In Pshop, you can use Bicubic Sharper (in the image size dialog box) for a better quality downsample. Or you can use bicubic and then manually work with Unsharp Masking or some other sharpening technique (takes longer, but more control).

    I also disagree that JPEG is so bad. I agree that it should be avoided if you're going to keep editing the file (because you want to avoid repeated compressions), but if you're just opening, resizing, sharpening, saving, and importing into InDesign, then JPEG (with high quality/low compression) is a very good option. Yes, it degrades the image, but only a very small amount. At maximum quality, virtually no one would be able to tell (if it's a photograph from a digital camera).

  • November 14, 2010 at 7:54 am #57732
    Theunis De Jong

    Member

    Hi David!

    My “it doesn't matter where you downsample” is based on the fact that, from the point of view of the final output, you should always supply more than enough pixels. I.e., for a 120 lpi screen show it seems you'd need no more than 150 dpi, but it's highly recommended to go no lower than 300 dpi. Surely any (un)sharpening at the individual pixel level would then be invisible?

    (Actually, this is equal to your thumbs up for JPEG. Any compression artifacts ought to be virtually invisible on high rez output — if and only if in its entire Save history only the highest possible quality was chosen.)

  • November 14, 2010 at 9:53 pm #57737
    Mayoor Chheda

    Member

    The intended output is indeed print – its going to be printed via sheetfed offset on coated paper. The reason for my asking whether to save in JPEG vs PSD was that saving in PSD format results in a much bigger file size when compared to saving in JPEG. It hardly matters nowadays, but still reducing the file size results in faster InDesign response

  • November 15, 2010 at 3:45 am #57738
    Anonymous

    Inactive

    David I believe I asked this very question a few years ago – but I cannot find the blog post?

  • November 15, 2010 at 6:34 pm #57754
    Alan Gilbertson

    Participant

    mayoor said: … I wanted to know whether I should first use Photoshop to reduce the size of the images to about 3 inches & the resolution to 300 ppi. Would doing this degrade the image quality. After reducing the size & resolution, should we save in JPEG format or as PSD files.

    ---

    I'll give you my two cents on this. As David says, reducing image size in Photoshop gives you more control. It's also true that you might or might not need that.

    If your output quality is critical (a fine art book, for example, or a very high end magazine) with a 175+ lpi screen or >200 “lpi” stochastic screen, then go ahead and resize in Photoshop. Save as a PSD for future use and repurposing. If you need to make more adjustments than just resizing, definitely save as PSD in case you need to tweak later. If it's memory or performance that's the problem, then save as PSD and then additionally save as jpeg for placing in ID.

    If you or your clients are very quality conscious, always save as PSD if you will be using the image for different purposes. Use the Smart Filter feature in CS4/5 so you can adjust the sharpen for the specific output. Screen, magazine print, newspaper print, inkjet print, poster, billboard and digital display all have different optimum sharpen settings.

    If output quality is normal (regular book or magazine printing, say), then unless you need to adjust brightness, contrast, sharpening, etc., you will save time by placing the original jpegs and letting InDesign take care of the downsampling, because there won't be any problem with the final printed product. This can be important if you have a large number of images to place. (Keep in mind, though, that almost any digital capture needs sharpening for intended output.)

    I use both workflows, according to need. Unless you can guarantee that an image that could be reused won't be opened, saved, opened a month later, saved, open in November, saved… it's best to have a policy that heads off compression artifacts before they ever have a chance to form, and save as PSD. Always saving at quality 12 slows down, but won't eliminate, image degradation.

    Even jpegs fresh out of the camera can have compression issues unless they were captured at the highest quality jpeg setting. Let's not even discuss images that come off the web (always super-compressed), and that the client wants to use full page, full bleed on the cover of his spiffy new brochure…

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