Alpha mask on TIFF patch files bug in 3.1.2 ? V4Beta3 ?

[g8dhe]

Hi, It appears that the Alpha mask on TIF patch files isn't being respected in the latest version;
Version 3.1.0 x64bit

Version 3.1.2 x64bit

[Hopki]

Hi
I have just compaired V3.1.0 and 3.1.2 and the later gives a better result?
Can you send me your patch tiff image and if you have it the PSD file?
Regards
Hopki

[g8dhe]

You have a PM.

[Hopki]

Hi Geoff
All I can do at this stage is Bug Track it, please see Issue #395
Hopki

[g8dhe]

Thanks Martin, looks like I'll have to hold with 3.1.0 for the time being !
Out of interest what format file did you use earlier that seemed to work ok, I could switch to that for the moment?

[Hopki]

Hi Geoff
Today I have tried the following files:
TIFF with transparency = OK
Tiff with Mask = OK
PNG = OK
Reduced quality PNG 24 (save for web) = OK

The following are some of my tests, I have put the patches in the sky to see any artefacts easier:
Tiff with transparency (no mask used)

tiff.swf

(1.22 MiB) Downloaded 8893 times

The next is the save for web png 24:

png 24.swf

(1.22 MiB) Downloaded 8889 times

However the image you sent me does produce artefacts?

The patches I have used are here if you want to have a test:

patches.zip

(205.14 KiB) Downloaded 318 times

Regards
Hopki

[g8dhe]

Ah ha interesting, tried your patches all looked fine, scratched head....only real difference was your background (masked) was Black, mine was White (masked), so changed colour of white text, changed colour of Black background to White, saved and repeated test - problem reappears!;

as a check I changed my masked background to Black and the problem is reduced but not totally eliminated;

So they problem appears to be associated in some way with the colour of the masked background....maybe ... my changes were made with PaintShop Pro XI so there might be something involved there of course !

Edit: OK so revise the above - its not the colours it appears to be differences in saved file formats or something about the way that PSP saves files!
Here is a comparison of top left your original file, bottom left my saved version of it (LZW compression) top right my saved file no compression;

The original file appears to be 3.54MBytes, whilst the same file saved by PSP un-compressed is 1.77MBytes and the third one compressed using LZW is as expected much smaller.
Not sure where we go from here, but if Thomas wants sample files they are available here with all the variations possible in PSP

[g8dhe]

Has this been looked at in the current V4 beta at all ?
Using the workaround mentioned above reduces the problem but I can still see the problem in V4 beta1/2/3 ....

[smooth]

Graphics with transparencies should be saved as .png-24
Use Photoshop Save for Web option .png-24

Regards, Smooth

[thomas]

I think I have looked into this, but can not remember the outcome. To avoid this, I have added it now to the bug tracker Issue #614.

[g8dhe]

Thanks Thomas! If you need any further test files please shout.

[thomas]

Hello Geoff,

I have now tried to reproduce the bug, but it looks like this is a general TIFF file format problem as some of your files can not even be handled by Photoshop correctly. TIFF has so many internal file formats that we can not support all of them as the specs are not even clear to begin with.
The safe way is to use uncompressed TIFF or as mentioned by smooth: PNG-24 is always a good and well defined solution.

[smooth]

It would appear Geoff is using (Free) Irfanview as his image program.
Irfanview can also generate and save to .png-24 format with IrfanView plug-ins.

irfanview_save_for_web_png-24.jpg (57.6 KiB) Viewed 10422 times

irfanview_plug-in.jpg (95.56 KiB) Viewed 10422 times

The IrfanView Plug-ins can be downloaded from here

Please understand though the industry standard is Photoshop and this is what 98%+ of answers refer to when talking image formats.

Regards, Smooth

[g8dhe]

Thanks but no I do have Ifranview but only use it for creating .ICO files.
The main image editing software is PaintShop Pro. Appreciate that there can be so many different internal formats within TIFF, but it seemed to change between earlier versions, maybe you changed a library or a library was altered with 3.1.2.
Anyway I'll see what works with PNG-24, thanks for taking a look Thomas

[thomas]

Thanks but no I do have Ifranview but only use it for creating .ICO files.
The main image editing software is PaintShop Pro. Appreciate that there can be so many different internal formats within TIFF, but it seemed to change between earlier versions, maybe you changed a library or a library was altered with 3.1.2.
Anyway I'll see what works with PNG-24, thanks for taking a look Thomas

Yes, I have changed the library to the new libTiff 4, and this may be the reason for the changed behaviour.