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TIFF filesize trebles when saving in PE14

Discussion in 'Digital Image Editing & Printing' started by Ray Proudfoot, Oct 3, 2017.

  1. Ray Proudfoot

    Ray Proudfoot Well-Known Member

    I'm using VueScan Pro to scan and save as TIFF files. When VueScan saves them the filesize is around 50Mb for a 35mm colour negative.

    But when I open it in PE14 and refine the image when I save it as a TIFF the file size doubles or trebles to 100-150Mb. Seems there's no difference whether compression is used or not. :(

    How can I reduce the size of these TIFF files?
     
  2. El_Sid

    El_Sid Well-Known Member

    Tiff files do tend to be large as they are 16bit and either uncompressed or use lossless compression. When you 'Save As' a TIFF file you should see a set of compression options, typically uncompressed, LZW and JPEG compression. Uncompressed will naturally produce the biggest files. LZW compression is what's known as a lossless compression using an algorithm that repacks the data in a more space efficient manner without any loss of said data - the problem is that unless the file contains a lot of even toned area, eg a big blank sky, the extra compression is often minimal. JPEG compression is a lossy format meaning that the algorithm used not only repacks the data but uses a certain amount of data substitution - effectively it average out areas of tone that are similar within a certain value band and then stores the average value as a pixel range rather than pixel by pixel. It may also reduce the file to 8bit instead of 16 (I've never used it myself). The net result is a much smaller file but at the cost of lost data that cannot be recreated on opening, the amount of data lost and thus file size reduction increases as you reduce the 'quality' value - high quality settings minimize loss bet produce bigger files, low quality the reverse...

    You could try saving the intermediates as PSD files (PS native format) as this seems to produce slightly smaller files, the downside is that as a proprietary file there's no guarantee that other software will read it or read it accurately.

    I always save my finished files as JPEG at maximum quality, which I find perfectly satisfactory for print and screen/projectors use, but I do also keep PSD copies of the intermediate files as well.

    It may also be worth checking your scanner settings too. First check the maximum native resolution of the scanner as it's generally better to avoid using any greater resolution as these are interpolated from the native resolution and can usually be reproduced more effectively in Photoshop anyway. Also tailor your scan size to the expected output size, there's no point in scanning for A3 output if it's only going to be printed at 6x4 or used for the web.
     
    Ray Proudfoot likes this.
  3. Ray Proudfoot

    Ray Proudfoot Well-Known Member

    Thanks Nigel. There must be some fundamental differences in how VueScan saves a TIFF and how PE14 does it. The compression option - LZW - makes no real difference. The file size is around double that of the VueScan-saved TIFF.

    I've got a decent workaround. After generating a TIFF in VueScan I'm loading it into the RAW editor in PE14. The good news is that if you get the settings right in VueScan the two clipping warning flags are both black suggesting the image requires little manipulation. Just a boost in contrast is all that's required but I'm careful to ensure those flags stay black.

    I don't bother saving the TIFF with PE14. I realise that means the changes are lost but the changes I'm making are pretty minimal anyway. There are a couple of images in my other thread and those look good on an ISF-Calibrated OLED TV so I know the colour balance and other settings are good.

    I'm reluctant to save as PSD as that would always require PE to open them. I think the compromise I've decided on is reasonable and ensures file sizes don't go daft. They're around 52Mb each and I'm scanning at 4000 as that is what the Coolscan V is capable of.
     
  4. PeteRob

    PeteRob Well-Known Member

    Probably it is the bit depth. I am not at home so I cannot check the vuescan options to see if you can select 8 or 16 bit.
     
  5. taxor

    taxor Well-Known Member

    My NikonScan files save at around 115mb for a 35mm scan so it sounds about right to me. Opening/saving in PS doesn't increase file size for me. I always save as TIFF or (when I want to save an alpha channel) PSD
     
  6. Ray Proudfoot

    Ray Proudfoot Well-Known Member

    Would it be desirable to save at 8 bit? I've closed down my scanning PC so can't check VueScan settings but would imagine it defaults to 16-bit.
     
  7. Ray Proudfoot

    Ray Proudfoot Well-Known Member

    That matches the file size when saved with PE14. It suggests Vuescan is saving at 8-bit. But that would be odd wouldn't it?
     
  8. PeteRob

    PeteRob Well-Known Member

    The vuescan manual is online - it suggests 8 bit (per channel) is the default

    quote
    This option describes the resolution of the cropped TIFF file, in bits per pixel. It should normally be set to 24-bits per pixel, since many image editing programs are unable to read TIFF files with higher bit depth than this.

    If you select 8 bits or 16 bits, the file will be saved in black/white format.

    Professional Option: This option is displayed when Output | TIFF file is set.
    unquote
     
  9. Ray Proudfoot

    Ray Proudfoot Well-Known Member

    @PeteRob, I haven't changed any TIFF settings so it appears the file is being saved at 8-bit which makes sense given the file size. But it's definitely a colour file so the black/white bit is confusing.
     
  10. PeteRob

    PeteRob Well-Known Member

    Without colour it is just storing luminance so only needs 8 bit (cf 24) or 16 (cf 48)
     
  11. Ray Proudfoot

    Ray Proudfoot Well-Known Member

    Sorry but I’m confused. It is a colour image. Are you saying colour is not stored in an 8-bit image?
     
  12. PeteRob

    PeteRob Well-Known Member

    (R,G,B) 8 bit for R, 8 bit for G and 8 bit for B. An 8 bit colour image contains 24 bit of information.
     
  13. Ray Proudfoot

    Ray Proudfoot Well-Known Member

    Right, so an 8-bit image does contain colour. Just less shades of grey than a 16-bit image I assume. Is 8-bit sufficient for a quality image? I’ll experiment tomorrow.
     
  14. PeteRob

    PeteRob Well-Known Member

    Yes. Yes fewer brightness levels and Yes.
     
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  15. Terrywoodenpic

    Terrywoodenpic Well-Known Member

    when you save it in PE14 are you saving any layers with it? they will add massively to the size.
    are you saving the PE14 file as 16 bit that will also increase the size. a 16 bit file contains massively more individual colours. most of which you will never ever be able to see on a screen.

    I generally work in 16 bit but finally save in 8 bit.
     
  16. Ray Proudfoot

    Ray Proudfoot Well-Known Member

    @Terrywoodenpic , I'll need to check if the layers option is checked. I'm pretty certain I'm saving in 16-bit which would explain the huge file sizes. I'll check tomorrow and switch to 8-bit and monitor image quality.

    I have a OLED TV which can display in 10-bit on Sky Q. Would I be correct in assuming most broadcasts are in 8-bit? If so choosing that option for saving TIFFs would appear not to be a problem.
     
  17. Terrywoodenpic

    Terrywoodenpic Well-Known Member

    almost certain that any TV will display photographs in 8bit in any event you would never see the difference. Most TV's will only read Jpegs and not any variety of tiff.

    However it is worth doing your PP in 16 bit as it is a bit like rounding up.
    If you wanted to do a set of accounts you might want to round up at the end, to the nearest pound
    If you rounded up all the individual entries first, you would get a far different and inaccurate result.

    So it is with colours, It is far more accurate to work with all the available data for your calculations(adjustments), and only throw away the surplus, what would be invisible data, at the end.
     
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  18. Ray Proudfoot

    Ray Proudfoot Well-Known Member

    I can confirm PE14 was set to save in 16-bit which explains the huge file sizes. I’ll adjust Vuescan to output in 16-bit, make necessary adjustments and then save in 8-bit. Good tip Terry. :)
     
  19. Eye Robot

    Eye Robot Well-Known Member

    Just for the record, Gimp, Faststone and Irfanview can open my PSD files (from PSE10), but all the layers etc are lost as you would expect.
     
  20. Terrywoodenpic

    Terrywoodenpic Well-Known Member

    Not lost just flattened into the image.

    A PSD file is a sort of home brew tiff with additions.
     

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