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Thread: Please explain;::::::::::

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    Please explain;::::::::::

    ..........in simple terms; why a 28 MB raw image turns into 120 MB file when converted in Lightroom to PSD. No corrections have been done to the image before converting to PSD


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    Member Calxoddity's Avatar
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    Ian,
    It doesn't have to be a raw file for this to happen - if you save a jpeg as a psd it also blows out big time. With jpeg > psd it's understandable, as jpeg is compressed. I suspect psd is not a lossy format and also doesn't compress, so with raw it's taking a lot of data to describe the raw sensor data in a form that's reusable and consistent.

    It's a pain though - i created a nice panorama last night from 8 x 5MB NEFs and the resulting psd file is 241MB!! I wondered why it was slow to open until I saw the filesize.

    Regards,
    Calx
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    A royal pain in the bum! arthurking83's Avatar
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    PSD must have some similarities with TIFF.

    I edited a 19Meg NEF the other night and made a few edits.. basic edits like WB and some contrast adjusments, protected highlights.. and not really all that much else.. but the temporary TIFF file(using CaptureNX) blew out to over 240Mb.
    Capture edits the NEF by using TIFF format as the image represented on screen(after all, the RAW file is not an image, but an amalgamation of digital data trying to describe an image.

    You were lucky to only get it to blow out to a 120Mb file!

    That's normal.
    PSD and TIFF are terrible formats to save too as they are so large.(I assume PSD's are slightly less so than TIFF's and should really only be used for printing purposes.
    Your RAW images shoudl be saved as RAW images for the sake of space conservation(and converted to high quality raster images for printing only)


    those file sizes are a good reason to why it can make a difference to have a separate scratch disk (NX would be unusable if I didn't have a separate disk for the cache files)

    Now, imagine how those 50Meg Nikon D3x NEF's must blow out too!
    Last edited by arthurking83; 26-04-2009 at 1:53pm.
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    I have recently swapped from saving as TIFF's to saving as PSD files on occasion. Especially when I have several layers and want to retain those for future adjustments. If you save a file that has layers as a PSD, it will be BIG, cause PSD saves all the layer data as well. So make sure you flatten layers before saving if you are using PSD (and don't have a need to revisit those layers in future).
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    So make sure you flatten layers before saving if you are using PSD (and don't have a need to revisit those layers in future)
    Rick am i right from your statement in assuming that once you flatten layers you can't rework them? Still trying to get my head around layers ..
    Julie

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    Quote Originally Posted by Jcas View Post
    Rick am i right from your statement in assuming that once you flatten layers you can't rework them? Still trying to get my head around layers ..
    If you flatten them and still save as PSD, you can still rework, I believe so.

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    Administrator ricktas's Avatar
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    If you flatten them you end up with one layer only. Yes you can start again with the RAW file, but once you flatten it and save it, you are left with only the one (background) layer. So say you did some selective colour work, you cannot just go back to that layer and adjust it, whereas if you save it as a PSD with the layers intact, you can.

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    Thank you both for the reply ..

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    Thanks for joining in and replying; although I still don't understand how an image can grow by 700% with "nothing" been done to it. I was told from somewhere else that PSD files already have the layers built into all files and therefore the massive size. Maybe time to reinvent PSD files

    This link may be of interest; and it may really fire it up. http://www.kenrockwell.com/tech/raw.htm. I was using raw with jpeg when photographing however Lightroom may have me changing that very soon. I was using the raw as a back up for when I got it wrong (too often & always the very best photo/s ) and was happy with the results from the jpeg files.


    Cheers

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    Without geting into the RAW v JPG debate, I stopped reading when I got to this " It took a half hour to download the images from the 1 Gig flash card".
    I'm sorry but if he claims it takes that long to download a one gig card, he has lost any creditability for the rest of the article as far as I am concerned.

    Cheers David
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    can't remember Tannin's Avatar
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    Quote Originally Posted by IanB View Post
    I still don't understand how an image can grow by 700% with "nothing" been done to it.
    It's actually quite simple: it happens because Adobe have an incredible talent for writing bloatware. Consider the following. It's part of the source code for Xee, a fast image viewer for the Mac. You don't have to follow the detail of the code, just understand that anything after a pair of slashes // is a comment by the programmer (usually placed as a reminder to anyone who comes along later and needs to rework the code for some reason).


    if(layerlen>0) layers=[XeePhotoshopLayerParser parseLayersFromHandle:fh parentImage:self alphaFlag:&hasalpha];
    [fh seekToFileOffset:maskoffs];
    uint32 masklen=[fh readUInt32BE];
    [fh skipBytes:masklen];
    while([fh offsetInFile]+12<=imageoffs)
    {
    uint32 sign=[fh readUInt32BE];
    uint32 marker=[fh readUInt32BE];
    uint32 chunklen=[fh readUInt32BE];
    off_t nextchunk=[fh offsetInFile]+((chunklen+3)&~3);
    // At this point, I'd like to take a moment to speak to you about the Adobe PSD format.
    // PSD is not a good format. PSD is not even a bad format. Calling it such would be an
    // insult to other bad formats, such as PCX or JPEG. No, PSD is an abysmal format. Having
    // worked on this code for several weeks now, my hate for PSD has grown to a raging fire
    // that burns with the fierce passion of a million suns.
    // If there are two different ways of doing something, PSD will do both, in different
    // places. It will then make up three more ways no sane human would think of, and do those
    // too. PSD makes inconsistency an art form. Why, for instance, did it suddenly decide
    // that *these* particular chunks should be aligned to four bytes, and that this alignement
    // should *not* be included in the size? Other chunks in other places are either unaligned,
    // or aligned with the alignment included in the size. Here, though, it is not included.
    // Either one of these three behaviours would be fine. A sane format would pick one. PSD,
    // of course, uses all three, and more.
    // Trying to get data out of a PSD file is like trying to find something in the attic of
    // your eccentric old uncle who died in a freak freshwater shark attack on his 58th
    // birthday. That last detail may not be important for the purposes of the simile, but
    // at this point I am spending a lot of time imagining amusing fates for the people
    // responsible for this Rube Goldberg of a file format.
    // Earlier, I tried to get a hold of the latest specs for the PSD file format. To do this,
    // I had to apply to them for permission to apply to them to have them consider sending
    // me this sacred tome. This would have involved faxing them a copy of some document or
    // other, probably signed in blood. I can only imagine that they make this process so
    // difficult because they are intensely ashamed of having created this abomination. I
    // was naturally not gullible enough to go through with this procedure, but if I had done
    // so, I would have printed out every single page of the spec, and set them all on fire.
    // Were it within my power, I would gather every single copy of those specs, and launch
    // them on a spaceship directly into the sun.
    //
    // PSD is not my favourite file format.
    if(sign!='8BIM') break; // sanity check
    switch(marker)
    {
    case 'Lr16':
    layers=[XeePhotoshopLayerParser parseLayersFromHandle:fh parentImage:self alphaFlag:NULL];
    break;
    case 'Mt16':
    hasalpha=YES;
    break;

  12. #12
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    Quote Originally Posted by pommie View Post
    Without geting into the RAW v JPG debate, I stopped reading when I got to this " It took a half hour to download the images from the 1 Gig flash card".
    I'm sorry but if he claims it takes that long to download a one gig card, he has lost any creditability for the rest of the article as far as I am concerned.

    Cheers David
    so lets see if i have this correct... hehas lost credibility with you because he has a slow computer?


    anyhow layers aside, raws are compressed, psd arent... simple

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    Not the fact he has a slow computer, but that it has no bearing on his argument what so ever, he is saying that jpg is as good as raw in regards to image quality in most (nearly every) situation, what has transfer speed got to do with image quality ?

    Cheers David

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