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[Solved] PNG Crop Grows Drastically
Posted: Sat May 23, 2020 4:19 am
by comccoy
I have a bunch of portraits I have been scanning at 1200x1200 ppi, 24bit, 16.7 million colors and saving as PNG (Epson Expression v600). As the masking for the scan is a bit inaccurate I pad them slightly and crop them post scan. I am finding that the files are growing drastically when I crop (or any adjustment) and save and it looks like Graphicconverter is removing the compression and forcing them from the 1:3 or 1:2 compression I started with to 1:1.
How can I keep or redo the lossless PNG compression?
Re: PNG Crop Grows Drastically
Posted: Sat May 23, 2020 11:37 am
by forum_adm
Please check the PNG save as options.
- Screen Shot 2020-05-23 at 11.36.jpg (110.75 KiB) Viewed 3402 times
What did you select?
Also, did you maybe save with a custom icon in the resource fork?
Thorsten
Re: PNG Crop Grows Drastically
Posted: Sat May 23, 2020 11:46 am
by forum_adm
Please e-mail the file zipped to
support@lemkesoft.de if you still have problems with the file size.
Re: PNG Crop Grows Drastically
Posted: Sun May 24, 2020 1:50 am
by comccoy
Re: PNG Crop Grows Drastically
Posted: Sun May 24, 2020 7:54 am
by forum_adm
The filter None cause the size change.
You get the best results with automatic. But that is very slow. Because it tries for all image lines each filter and compares the results.
Thorsten
Re: PNG Crop Grows Drastically
Posted: Sun May 24, 2020 9:02 am
by forum_adm
Please download the latest BETA:
http://www.lemkesoft.org/beta.html
and select as filter the new Dynamic.
That is much faster than the old Automatic and should create a smaller PNG.
Thorsten
- Screen Shot 2020-05-24 at 09.01.jpg (119.48 KiB) Viewed 3385 times
Re: PNG Crop Grows Drastically
Posted: Sun May 24, 2020 2:48 pm
by comccoy
So my original was 60.8MB. The None filter produced an 85.4MB file. With Dynamic it is 64.3MB. Thank you for your help!
For my mind I have a hard time understanding how I take a 51.5 megapixel image, crop it and reduce the actual number of pixels and end up with a larger file size. I think I just don't understand the algorithms that "build" what is displayed on the screen.
I tried Preview and it cropped up to 69.6MB.
Thank you so much for your help. I will work with the beta for now.