Exported *.png images seem to have black background when it should be transparent

[HarryPutnam]

Running Designer pro 6.1.2.13287 on Windows 7 Home Premium

I'm probably bumbling around and buggering up the export of png formatted images, but it appears something besides transparency is getting exported as backbround.

In the screen shot inlined below you see the artwork inside a xara document ready for exporting.



I do `Select all' then export to png.
The poorly drawn green arrows were added in photoshop to show the area I'm talking about. The xara document which is apparently also getting exported in some way.

At least certain other tools see a black background in that area. Not all tools have that problem with the image. For example; photoshop sees only transparency there.

But when I browse the exported *.png files with `Epson print CD', it sees black in that area as illustrated by the screen grab below:



The first two images look clean as expected (I'll explain in a moment) but the third (the one that hasn't been cleaned in Photoshop) shows the black background in that area.

The first two were cleaned up in photoshop and now appear clean as expected.

So to get a usable image for import into Epson's tool I must:

1) Export as PNG from Xara

2) Open with Photoshop and run thru a procedure where anything outside the outer blue ring in the image is deleted.

(Even though PS only sees transparency, if I select everything from the blue ring outward and delete it, saving back to png, then Epson's tool sees transparency there)

3) Import into `Epson Print CD' and print the graphic to a printable DVD.

How can I skip the second step? That is, how can I get a clean export in step one? What is it that some tools are seeing as black background?

[molucca]

I have a program that shows the transparent area as black, and from Photoshop something somewhat strange. The graphics are fine however. For me, it is just the way the alpha channel is displayed. I would look a little more and see if this may be the case.

Rich

[GerryI]

While I agree that some programs do display the transparent areas in different ways, this doesn't explain why the PNGs from DP and PS behave differently. Are they "True colour+Alpha" PNGs or only 256 colours? Can you attach a couple of the files, the one from DP and the same image after the PS procedure? I presume there is a difference in how the fully transparent pixels are stored; DP definitely uses fully transparent black, e.g. the RGB value is 000000 with the alpha value set to fully transparent. It is possible (though I find it unlikely, maybe it is done for backward compatability with apps that don't support transparency properly) that PS stores the background pixels with an RGB value of white. If this is the case then there may be an option in PS to control this though I don't remember seeing one.

Thanks,
Gerry

[handrawn]

when you export from Xara Designer, if you select colour depth 'true colour + alpha' from the palette options in the export dialog box, you should not need to use phototshop to clean up the image [alpha [channel] => transparency]

EDit: Gerry got there first

[HarryPutnam]

when you export from Xara Designer, if you select colour depth 'true colour + alpha' from the palette options in the export dialog box, you should not need to use phototshop to clean up the image [alpha [channel] => transparency]

EDit: Gerry got there first

Thanks... but exporting in exactly the way you describe does not do the job for at least one SW program (Epson Print CD [Version 2.00.00A])

I hope it isn't too confusing; I've posted and linked 4 images as described below:
(It seemed kind of a hefty load to put on the forum so what I've done is linked 4 images)

1 and 3 are original images, 2 and 4 are screen shots of those originals as they appear inside Epsons `Epson Print CD' software (See link to all 4 images at the end)

Detailed description of images by name:
1) 1_Image.png is the image as exported from xara with `True Color + Alpha set

2) 2_Image_screengrab.png is a screen grab of how that exported image (1_Image.png) looks inside the 'Epson print CD' tool

3) 3_Image_CleanedInPhotoshop.png is Image1.png after it has been opened in PS and all pixels outside the outer ring in the image have been deleted.

4) 4_Image_screengrab.png is a screen grab of how that cleaned image (3_Image_CleanedInPhotoshop.png) looks inside the 'Epson Print CD' tool

So something is changing that lets Epsons tool see transparency once the image has been cleaned in PS.

See all 4 images HERE

[HarryPutnam]

Thanks... but exporting in exactly the way you describe does not do the job for at least one SW program (Epson Print CD [Version 2.00.00A])

[...]

See all 4 images HERE

It dawned on me belatedly after closing the browser, that the cgi script in above URL would not give access to the original images, only a visual read into a webpage. That is fine for a quick look at them all, but not fine if anyone wants to examine the original

Below are links to the original individual images:
1) 1_Image.png - exported from Xara with `True Color + alpha' set

2) 2_Image_screengrab.png - Screen Grab of 1_Image.png as it appears inside `Epson Print CD'

3) 3_Image_CleanedInPhotoshop.png - 1_Image.png opened, cleaned and saved in Photoshop

4) 4_Image_screengrab.png - Screen grab of 3_Image_CleanedInPhotoshop.png as it appears in `Epson Print CD'

[handrawn]

Hi Harry

try another format - export from Xara as PSD, which I feel sure Epson Print CD will read, do you get the same problem - a few years back it was common for some programs not to support, or fully support, transparency in PNG - if the Epson program is recent that's unlikely bit you never know - which is basically what both Rich and Gerry referred to

and posting up files as Gerry suggested might help determine the problem with the PNG's EDIT - sorry this you've now done - me not awake yet

[handrawn]

Also I see that the actual circle itself has a degree of transparency in the xara image - does it work better if you remove this so that the circle is solid colour?

[molucca]

In the first case, the Xara alpha channel displays as black. With Photoshop the alpha channel displays white. Probably just the way the Epson program displays transparent graphics.

Rich

[HarryPutnam]

Also I see that the actual circle itself has a degree of transparency in the xara image - does it work better if you remove this so that the circle is solid colour?

I've half forgotten already how I arrived at the original image posted about. So I've created a new one using no transparency from outer circle inwards. Of course every thing outside the outer circle should be transparent.

Exported as png and with True Color + Alpha set, still shows up with black background
inside the Epson tool

As to your request to export in another format:

Handrawn wrote:

try another format - export from Xara as PSD, which I feel sure Epson Print CD will read

Actually, no, the Epson tool only sees *.jpg ,*.png and *.bmp. I couldn't find a definitive statement concerning acceptable formats in the Epson tool's help file to post here, but experiment has shown that neither *.psd,*.tif, *.tga, or *.gif are viewable at all.

I did discover that with the right settings, exporting as *.bmp will be seen correctly inside the Epson tool (Epson Print CD version 2.00.00A).
(However, exporting as *.bmp creates a very much more massive file even than *tif)

That *.bmp works as expected, perhaps gives an additional clue...? Or at least provides a way to get the job done with one less step. (cleaning in PS).

Links to original files:
Exported.png - exported with True Color + alpha but no transparency used in the artwork itself.

[NOTE: The *.bmp format is orders of magnitude bigger so may take awhile to load]
Exported.bmp - Exported with `True Color' (no `+ Alpha' available in *.bmp settings)