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Thread: Tiff, JPG pixel degradation

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    Senior Member johnnygoesdigital's Avatar
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    Tiff, JPG pixel degradation

    Most of us shoot RAW, but when converted most likely use Tiff's, Jpg's, Dng's, psd, etc. After adding adjustments like contrast, highlights, crop, etc., do I lose pixels each time I save a file? Does the image resort to interpolation to compensate for the missing pixels? Obviously, I want the best quality and know that a Tiff has better quality than a Jpg, but most if not all of the print labs that have online ordering (ROES) only upload Jpg's. I notice this when cropping an image, after the crop, the image didn't have the resolution it did prior to the crop. Perhaps, I missed class that day they talked about this.

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    Subscriber & Workshop Member GrahamWelland's Avatar
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    Re: Tiff, JPG pixel degradation

    The thing to remember about jpgs for processed images is that you need to consider them as final output, not working files. If you save a jpg then yes every time you reload and save you will degrade quality.

    The general workflow I use is to process raw files to create raw & adjustments in Capture One. I output full res tiff files for Photoshop work or if that's not needed I'll output scaled & cropped & sharpened jpg files for upload or sending. In PS I always keep master files as PSD and then will OUTPUT to jpgs if necessary. I never save/edit/resave jpgs.

    Hope that helps. You can substitute Lightroom/Aperture etc for Capture One/Photoshop obviously.

    Btw, tiff files are lossless compressed so that is a valid output/working format if needed.

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    Senior Member doug's Avatar
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    Re: Tiff, JPG pixel degradation

    Adjustments in Photoshop should be done wherever possible as adjustment layers, which can either be saved independently of the TIFF file or saved as a layer in a PSD file. This preserves the original pixel data, applying the adjustments only once when you flatten the image for output. If you were to make several adjustments to the pixel data not using adjustment layers you can end up with gaps in your image histogram which is seen as a loss of tonal gradation.

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    Subscriber & Workshop Member GrahamWelland's Avatar
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    Re: Tiff, JPG pixel degradation

    +1 to what Doug says. Keep it all NON DESTRUCTIVE - layers and also increasingly I'm using smart objects in PS so even filter work can be revisited vs being baked into layers.

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    Senior Member johnnygoesdigital's Avatar
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    Re: Tiff, JPG pixel degradation

    I've been using Phocus and aperture and do work the file, first as a tiff and then as a jpg for viewing and in a few cases for upload to a printer for orders. Although, Ps, is an amazing program, I've yet to exploit its full potential. In most of my photography, I really just do slight adjustments, I don't want to alter the photo too much (purist) in Ps, but have noticed in aperture that the quality was not as sharp after adding an adjustment...hmmm.

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    Re: Tiff, JPG pixel degradation

    JPEG as originally defined is a lossy compression algorithm, which loses detail by definition.

    A lossless JPEG version was added to the standard some years ago. If you store and retrieve lossless JPEGs you should not suffer loss of information. This option should be present either as a check box or a slider control.

    Be careful if using this option, since an inadvertent save in the lower quality (lossy) mode will lose data that cannot be subsequently recovered.

    - Leigh

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    Re: Tiff, JPG pixel degradation

    if you are re-sizing your image from the native, pixels will have to change. PS offers a bicubic version for going each way, up or down. Do this as a next to last step, the very last step being the unsharp mask

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    Senior Member mediumcool's Avatar
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    Re: Tiff, JPG pixel degradation

    One slightly OT point is that higher bit depths (eg 16-bit vs 8-bit) allow more extreme adjustments before showing posterisation/gaps in the histogram. When I export from C1, itís usually in 16-bit/channel TIFF format (48-bit in RGB).

    When I go to Photoshop for further retouching etc., I always save masters in PSD formatóit saves more quickly, supports more PS file features, and has lossless compression (when Adobe included lossy compression in their TIFF options, in my opinion they violated the spirit of TIFF). I used to use TIFF for FreeHand and PageMaker documents, but InDesign supports PSD format, so I stick with that.

    JPEGs have a sequence of compression routines run one after another, and it is quite a primitive format as it was specified many years ago. Newer compression schemes such as JPEG2000 are lossy in a more elegant way but not popular. JPEG could perhaps be described as the Windows of the graphics world; ubiquitous and with very old foundations!

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    Senior Member mediumcool's Avatar
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    Re: Tiff, JPG pixel degradation

    Quote Originally Posted by johnnygoesdigital View Post
    I notice this when cropping an image, after the crop, the image didn't have the resolution it did prior to the crop.
    When you crop an image, you by definition end up with fewer pixels, whereas resolution is considered to be the number of pixels per inch or centimeter of the image (or screen).

    So after you crop, the resolution of the image is the same, but the pixel dimensions will be smaller.

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    Administrator, Instructor Guy Mancuso's Avatar
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    Re: Tiff, JPG pixel degradation

    Good rule of thumb and i tell every client of mine this as I deliver both a full res. Tif and Jpeg to them . Jpegs are for web, e-mail and powerpoint and NOTHING else. The Tifs are for retouching , cropping and going to press or print. I also make the jpegs SRBG just for the web and powerpoint. Never confuse the two. Trust me they do
    Photography is all about experimentation and without it you will never learn art.

    www.guymancusophotography.com

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    Senior Member mediumcool's Avatar
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    Re: Tiff, JPG pixel degradation

    Quote Originally Posted by Guy Mancuso View Post
    Good rule of thumb and i tell every client of mine this as I deliver both a full res. Tif and Jpeg to them . Jpegs are for web, e-mail and powerpoint and NOTHING else. The Tifs are for retouching , cropping and going to press or print. I also make the jpegs SRBG just for the web and powerpoint. Never confuse the two. Trust me they do
    Right on. Rarely met a client who knew/cared about file formats; JPEG is what they mostly know, so JPEG is what they ask for.

    So I do almost the same as Guy; offer JPEG (but in lower resolution) for screen use, and the full-size file in TIFF format, stressing that that is the version to be kept as the *hi-rez* master for serious work, and I keep my masters in PSD format.

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    Re: Tiff, JPG pixel degradation

    Use a tool like Lightroom or C1 that can do most edits non-destructively. You then generate a TIFF for printing, JPEGs for web use, or whatever your needs are. There is no destructive editing to the original at all. I use LR3 with Nik tools, Pixmatic, NoiseNinja, etc as plugins for most things and very rarely launch PS anymore. I really only use it for perspective crops, everything else I need is done directly from LR3. C1 Pro is similar, and I think a better tool than LR3 in itself, but LR3 has a rich plugin ecosystem and some cataloguing features I find very practical so it's much more useful IMO...

    By the way, the non-destructive edits apply to much more than is easily accomplished in PS. Like you can apply the healing/spotting tools to clean up a raw file directly before you ever export it for any other use.

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