A save question

[bruce1951]

Just curious as to how PL is saving files.

eg. I have a single layer tiff. 160meg. I added 2 simple layers and save in PL format. Yet that PL file is 'only' 129meg.

Help me understand how PL can save in PL format with 3 layers, not loose any quality, and yet be smaller than the original tiff.

regards

[photoken]

This is a grossly simplified explanation, as I understand it:

When TIF images are saved with compression, a table of data needs to be created with a separate entry for each unique colour. Obviously, a 16-bit TIF has many more unique colours than an 8-bit image, so the corresponding data table will be quite large. This is why 16-bit compressed TIFs are notorious for having a larger file size than the uncompressed 16-bit TIF.

The native PLD format is simply using a more efficient storage algorithm for the original image data....

[bruce1951]

Thanks Ken. My main worry, as always, is any loss of data/quality. But if it's only internal house keeping then all's well.

regards

[Hoogo]

I guess the tiff and the other layers have a depth of 8 Bit? Then the layers should be compressed lossless as Png when you save.
Check the layer properties after saving, there should be an entry that tells about added picture data.

You can also find jpg there if you've loaded a jpg or another file format that embeds jpg. When you apply changes to the layer, these picture data is discarded. So as long as you do not alter a jpg layer, the original jpg is stored in the pld.