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Inspiring
July 21, 2022
Question

size matters

  • July 21, 2022
  • 3 replies
  • 876 views

I processed some scenics that are scans from slides, full frame, in topaz AI software.  Though the tiffs were originally saved compressed as LZW, they come out much larger, without the compression.  My website accepts up to 64M, and many are over 100M, eg example 143M.  I had a compress action but when it goes to save it says it will be larger with lavers.  I look and there is only 1 layer, that says layer 1.  I flatten anyway and it becomes background and saved, it becomes ~ 100M.  So then I go back to compress using LWZ and it is back to 143M.  I posted a similar thread about trying to reduce the size in 'image size' and also had images coming out larger instead of smaller when reduced there. What is going on? I din't want to have to go over every image and reduce each's measurements. When there were only a few I would do so and save with a minus (-) put after the name, but this is a lot of trouble when so many are coming out gigantic.

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3 replies

Legend
July 22, 2022

And quit using TIFF, PSD is generally more efficient. Or just put JPEG online.

Per Berntsen
Community Expert
Community Expert
July 21, 2022

Are these 16-bit files by any chance?

LZW compression will increase the file the size of 16-bit files.

ZIP compression will decrease the file size somewhat.

Inspiring
July 22, 2022

Where do I see the bit info?

Per Berntsen
Community Expert
Community Expert
July 22, 2022

So after looking at more image modes, it seems that I saved and processed in only 8 bit mode, and saved as LZW tiffs.  But after Topaz Picture AI worked on them, they became uncompressed and 16 bit.  Is there any advantage to making an 8 bit file 16 bits?  It can't add more data that's already gone,  just made it bigger, correct?  Or is it that the LZW compression save reduced them from 16 bits to 8 and the Topaz just restored it, but again, was the data lost irettrievably and the larger size has no merit?


I'm not familiar with Topaz Picture AI, but the three Topaz plugins I use, Sharpen AI, DeNoise AI and Gigapixel AI do not have an option to change the bit depth. Feed them 8-bit files, and 8-bit files are returned.

The LZW compression cannot cause this conversion either, so you must somehow have converted them to 16-bit yourself.

And you're right in assuming that there is no advantage to converting an 8-bit file to 16-bit.

 

IMO, there is no disadvantage to using Tiff. It is more widely supported than PSD, and also has slightly better compression, as far as I can remember from some tests I did years ago.

Derek Cross
Community Expert
Community Expert
July 21, 2022

Save as JPGs and to the dimensions you need and experiment with compression to get the smallest file size without too much image deterioration.