Displaying a PNG with alpha transparency?

[LindaSue]

In later versions of PSP, the options look like this:

[terrypin]

Just in case this might be part of the issue, how do you have your file format preferences set? This is how mine is set for PNG:

PNG Preferences.jpg

LindaSue, that's it - you're a star, thanks a bunch!

That's been driving me nuts. My setting was enabled. As soon as I unchecked it all the transparent PNGs that hartpaul, you and I have been discussing happily revealed their checkerboards.

A residual issue (I hate unsolved puzzles) is understanding exactly why that setting has this effect?

Hope you both have a great weekend. My own was in danger of being spoiled as I anticipated being stuck at my PC during some of tomorrow's Murray Wimbledon final.

--
Terry, East Grinstead, UK

[terrypin]

Hi Terry, just followed your steps in PSP8.00 on XP Home SP3 and got the checkerboard pattern with no problems.
In Irfanview double clicking that image and it shows as black rather than green which is how I believe Irfanview shows transparency in a png file (Irfanview 4.30).

Hi hartpaul,

See the good news in my post of a few minutes ago.

Many thanks for taking so much time and effort to help me isolate this vexing quirk. I thought I'd gone through all of PSP's settings looking for anything remotely relevant. But I clearly missed that one, despite its including the word 'transparency'!

--
Terry, East Grinstead, UK

[LindaSue]

The thing is that it doesn't explain why I don't see the checkerboard on your PNG image, Terry, but I'm glad that it's working for you now.

Another strange thing is that I used to have to set that option the opposite way and at some point in time my PNG transparency stopped working no matter what method I used to save them. The only thing that restored it was switching my setting as shown in my screenshot for all of my versions of PSP. I actually don't think that it's the correct setting and that something went wrong in PSP and it affected all of my PSP versions at the same time. I suspect that's what happened to you because I think you said that the transparency used to work for you, right? However, I did try changing my setting yesterday but I still couldn't see the checkerboard on your PNG even if I shut down PSP and reopened it after changing the setting in preferences. Very odd. Maybe I'll try it again today and see what happens.

[terrypin]

Just in case there's any ambiguity, can you confirm which 'your PNG' you mean. Can't check right now (this comes from my iPad) but I suspect that may be down to my mistake. Until this breakthrough my only test for whether a PNG contained transparency was to open up my video editor, MAGIX Movie Edit Pro, and import the PNG there. So I may have been wrong at some point in my descriptions.

Another puzzling thing is how I got those rare displays of checkerboard even before unchecking this crucial setting? Needs more methodical testing - but too fine an afternoon here to do it now!

Terry, East Grinstead, UK

[LindaSue]

Just in case there's any ambiguity, can you confirm which 'your PNG' you mean. Can't check right now (this comes from my iPad) but I suspect that may be down to my mistake. Until this breakthrough my only test for whether a PNG contained transparency was to open up my video editor, MAGIX Movie Edit Pro, and import the PNG there. So I may have been wrong at some point in my descriptions.

Another puzzling thing is how I got those rare displays of checkerboard even before unchecking this crucial setting? Needs more methodical testing - but too fine an afternoon here to do it now!

Terry, East Grinstead, UK

The one in your very first post in this thread. The file name is "Clock-Nohands-OnGreen-50-Alpha.png".

[terrypin]

The one in your very first post in this thread. The file name is "Clock-Nohands-OnGreen-50-Alpha.png".

OK, just checked and I hadn't made a mistake. It does show with checkerboard now for me.

(And it reminds me of another factor influencing my choice of a bright colour for some of my tests: it can help to spot transparency from the file's thumbnail.)

So it seems there's some other factor at work in your case. Just in case these offer any clue, here's what all 11 of my General Preferences look like. I've also included another arbitrary example of a PNG with transparency, this one made without using the Optimizer.

https://dl.dropboxusercontent.com/u/401 ... fs-All.jpg

https://dl.dropboxusercontent.com/u/401 ... laysOK.png


--
Terry, East Grinstead, UK

[LindaSue]

I wonder if something is happening when I save the file to my hard drive because it's not transparent for me in PSP, IrfanView, CompuPic or Photoshop.

[hartpaul]

Thats interesting. My PSP 8.0 does not have PNG in the File Format preferences. What version of PSP 8 do you have Terry?
So I cannot tick or untick "Load and save transparency from / to alpha channel" but was still getting transparency in all cases.

[LindaSue]

I'm using PSP 8.10. It was the final version of PSP8. It wasn't a patch or service pack. It was a completely new version with all of the previous patches included in it. Anyone who bought the CD version, and registered it, was sent a new CD in the mail when 8.10 was released. You had to uninstall your previous version of PSP8 before installing 8.10.

[hartpaul]

Mine was the boxed CD version with the large 437 page user manual. Jasc certainly looked after one in those days. I guess I did not register or was unaware - perhaps it was a mail in register rather than an online register back around April 2003 here in Australia.

[terrypin]

Mine is 8.10 but it was reached by applying the update patch, to 8.01 I think. (This discussion has me wondering exactly how I would completely reinstall PSP 8, as I don't appear to have the original CD if I ever did, only PSP 7.)

And applying the patch again was one of the steps I tried (in vain) before the mysterious fix.

I'm guessing that this issue is registry related. I don't recall ever using it but I see a tool in my download folder called ZapJasc.exe (google found over 500 hits) so that might be useful if you go down the re-install route, LindaSue.

I'd also been seeking help on this from a friend in my regular Magix forum, technically ahead of me on this stuff. He had this to say about 'the fix':

"That setting makes does not quite make sense!!!

The Alpha channel is a fourth 'colour' channel ie RGB + alpha is stored in the png image, why telling PSP to load/save display the alpha channel the background colour causes a solid solid instead of transparent is a bit of mystery.

In a png image a pixel can be set to a RGB combination (ie colour) or transparent as happens when the option you discovered is not checked or my method is used. When the option is checked then the pixel is still set to its original colour and the alpha channel now holds the transparency information.

Yet PSP appears to be ignoring this alpha channel."


--
Terry, East Grinstead, UK

[LindaSue]

Mine was the boxed CD version with the large 437 page user manual. Jasc certainly looked after one in those days. I guess I did not register or was unaware - perhaps it was a mail in register rather than an online register back around April 2003 here in Australia.

I was a private beta tester for PSP8 and Jasc sent us the boxed version (with the big manual) for free. Later, after they realized there were too many bugs to patch, they released the new 8.10 CD. I actually got two copies of the updated CD; one because I had been a beta tester and a second copy as a registered user because I had registered it online. As far as I can recall, they mailed them at no charge to all registered users no matter where they lived.

[LindaSue]

Paul, I'm not sure exactly what these two files are but one of them might be what you'd need to update PSP8 to 8.10.

http://www.corel.com/6763/psp_downloads ... 810enp.exe

http://www.corel.com/6763/psp_downloads ... 10entr.exe

PSP8.10 ReadMe: http://www.corel.com/6763/psp_downloads ... readme.pdf - I see this on page 3:

Added option to PNG Optimizer and File Format Preferences to save transparency data as an alphachannel or image transparency.

Terry, your friend is right. Having to switch the setting doesn't make sense but the important thing is that it solved your problem and mine.

[terrypin]

but the important thing is that it solved your problem and mine.

Did I miss a post? Does that mean you are now consistently getting checkerboard?

--
Terry, East Grinstead, UK