Index » PageStream Support » General » PageStream transparent PNGs - not truely transparent in PageStream
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2014-11-02 12:44:40 CT #1
Brent W. Santin
From: Canada
Registered: 2007-11-02
Posts: 105
 Hi,

I created some transparent PNGs in ImageFX on the Amiga. I used a true black R:0 G:0 B:0 to denote the transparent areas.

When loaded into PageStream (latest version for Windows) it looked good. The transparent areas of the PNG seemed transparent and I could see the background (which was a solid colour).

After rendering the completed work to a bitmap, I noticed a very faint difference between the solid green background of my work, and the solid green background showing through the transparent areas of the PNG image.  The difference was VERY faint, but I could see it.  Going back to the original PageStream document I took a good look and could see this difference too.

I loaded the rendered image into ImageFX and used it to identify the RGB values of the green background in the transparent areas of the PNG and outside it:

Outside PNG (correct background RGB): R:048, G:092, B:000
Showing through the transparent areas of the PNG: R:047, G:091, B:000

So there appears to be a math error in calculating the colour of tranparent areas in PNG images within PageStream.  Maybe it is counting from 0 to 255 whereas it should be counting from 1-256?

Anyway, it's not a hugely noticable thing, but it really bugs me.

Loading the same PNG into Inkscape, with the same green background, worked properly, there was absolutely no difference between the green background and the background showing through the PNGs transparent areas.

I can provide my original PageStream document or PNG if anybody needs to do a test.
2014-11-02 14:03:07 CT #2
Bart Mathias
From: United States
Registered: 2007-01-13
Posts: 320

Hello woodenflutes@yahoo.ca

I'm curious whether PageStream 5.0.5.8 on the Amiga would have the
same problem, but it's probably not worth your trouble to cure my
curiousity...

Bart Mathias

On 11/02/2014, you wrote:

> Hi,
>
> I created some transparent PNGs in ImageFX on the Amiga. I used a
> true black R:0 G:0 B:0 to denote the transparent areas.
>
> When loaded into PageStream (latest version for Windows) it
> looked good. The transparent areas of the PNG seemed transparent
> and I could see the background (which was a solid colour).
>
> After rendering the completed work to a bitmap, I noticed a very
> faint difference between the solid green background of my work,
> and the solid green background showing through the transparent
> areas of the PNG image. The difference was VERY faint, but I
> could see it. Going back to the original PageStream document I
> took a good look and could see this difference too.
>
> I loaded the rendered image into ImageFX and used it to identify
> the RGB values of the green background in the transparent areas
> of the PNG and outside it:
>
> Outside PNG (correct background RGB): R:048, G:092, B:000
> Showing through the transparent areas of the PNG: R:047, G:091,
> B:000
>
> So there appears to be a math error in calculating the colour of
> tranparent areas in PNG images within PageStream. Maybe it is
> counting from 0 to 255 whereas it should be counting from 1-256?
>
> Anyway, it's not a hugely noticable thing, but it really bugs me.
>
> Loading the same PNG into Inkscape, with the same green
> background, worked properly, there was absolutely no difference
> between the green background and the background showing through
> the PNGs transparent areas.
>
> I can provide my original PageStream document or PNG if anybody
> needs to do a test.
>
>
2014-11-03 08:10:47 CT #3
T.J. Zweers
From: Netherlands
Registered: 2006-02-07
Posts: 331
Hi,

I've read old mails about PNG and transparency (Transparency with PNGs). I see no solution mentioned. I searched the bug list at PageStream.org: nothing.
Strange thing that I use PNG's with transparency (not made by myself), and I don't see any faint background. Maybe I am not that critical. :-)
See: http://www.ligfiets.net/news/4784/vrijdagbericht-145.html (the Ellumiglow-logo is a PNG with transparency - click on the picture. Also the original, in PGS, doesn't have it also.)

Theo

woodenflutes@yahoo.ca [PageStreamSupport] schreef op 2-11-2014 om 21:44:
Hi,

I created some transparent PNGs in ImageFX on the Amiga. I used a true black R:0 G:0 B:0 to denote the transparent areas.

When loaded into PageStream (latest version for Windows) it looked good. The transparent areas of the PNG seemed transparent and I could see the background (which was a solid colour).

After rendering the completed work to a bitmap, I noticed a very faint difference between the solid green background of my work, and the solid green background showing through the transparent areas of the PNG image.  The difference was VERY faint, but I could see it.  Going back to the original PageStream document I took a good look and could see this difference too.

I loaded the rendered image into ImageFX and used it to identify the RGB values of the green background in the transparent areas of the PNG and outside it:

Outside PNG (correct background RGB): R:048, G:092, B:000
Showing through the transparent areas of the PNG: R:047, G:091, B:000

So there appears to be a math error in calculating the colour of tranparent areas in PNG images within PageStream.  Maybe it is counting from 0 to 255 whereas it should be counting from 1-256?

Anyway, it's not a hugely noticable thing, but it really bugs me.

Loading the same PNG into Inkscape, with the same green background, worked properly, there was absolutely no difference between the green background and the background showing through the PNGs transparent areas.

I can provide my original PageStream document or PNG if anybody needs to do a test.




-- 
Redacteur, vertaler, illustrator bij Ligfiets.net
2014-11-03 04:19:18 CT #4
Rodney Volkmar
From: United States
Registered: 2006-02-10
Posts: 60
did you use "Generate Mask" after you brought it in?

On Mon, Nov 3, 2014 at 12:10 AM, Theo Zweers tjzwrs@gmail.com [PageStreamSupport] <PageStreamSupport@yahoogroups.com> wrote:
 

Hi,

I've read old mails about PNG and transparency (Transparency with PNGs). I see no solution mentioned. I searched the bug list at PageStream.org: nothing.
Strange thing that I use PNG's with transparency (not made by myself), and I don't see any faint background. Maybe I am not that critical. :-)
See: http://www.ligfiets.net/news/4784/vrijdagbericht-145.html (the Ellumiglow-logo is a PNG with transparency - click on the picture. Also the original, in PGS, doesn't have it also.)

Theo

woodenflutes@yahoo.ca [PageStreamSupport] schreef op 2-11-2014 om 21:44:
Hi,

I created some transparent PNGs in ImageFX on the Amiga. I used a true black R:0 G:0 B:0 to denote the transparent areas.

When loaded into PageStream (latest version for Windows) it looked good. The transparent areas of the PNG seemed transparent and I could see the background (which was a solid colour).

After rendering the completed work to a bitmap, I noticed a very faint difference between the solid green background of my work, and the solid green background showing through the transparent areas of the PNG image.  The difference was VERY faint, but I could see it.  Going back to the original PageStream document I took a good look and could see this difference too.

I loaded the rendered image into ImageFX and used it to identify the RGB values of the green background in the transparent areas of the PNG and outside it:

Outside PNG (correct background RGB): R:048, G:092, B:000
Showing through the transparent areas of the PNG: R:047, G:091, B:000

So there appears to be a math error in calculating the colour of tranparent areas in PNG images within PageStream.  Maybe it is counting from 0 to 255 whereas it should be counting from 1-256?

Anyway, it's not a hugely noticable thing, but it really bugs me.

Loading the same PNG into Inkscape, with the same green background, worked properly, there was absolutely no difference between the green background and the background showing through the PNGs transparent areas.

I can provide my original PageStream document or PNG if anybody needs to do a test.




-- 
Redacteur, vertaler, illustrator bij Ligfiets.net




--
''Corporations are people. Money is free speech. War is peace. Freedom is slavery.
Ignorance is strength. telling the truth is a revolutionary act''
2014-11-03 05:19:41 CT #5
Brent W. Santin
From: Canada
Registered: 2007-11-02
Posts: 105
 Bard, as far as I know, the Amiga version of PageStream doesn't support transparent PNGs.
2014-11-03 05:24:35 CT #6
Brent W. Santin
From: Canada
Registered: 2007-11-02
Posts: 105
 Theo,

I couldn't see any problem with your ellumiglow logo (if I was looking at the right thing), althought the dithered background made it difficult to tell.

Did you lay this out in PageStream, though?
2014-11-03 16:07:53 CT #7
T.J. Zweers
From: Netherlands
Registered: 2006-02-07
Posts: 331
Oh, yes, I'll do all those illustrations in PGS.
I send you private the png.

Theo

woodenflutes@yahoo.ca [PageStreamSupport] schreef op 3-11-2014 om 14:24:
Theo,

I couldn't see any problem with your ellumiglow logo (if I was looking at the right thing), althought the dithered background made it difficult to tell.

Did you lay this out in PageStream, though? 


-- 
Redacteur, vertaler, illustrator bij Ligfiets.net
2014-11-03 09:01:15 CT #8
Brent W. Santin
From: Canada
Registered: 2007-11-02
Posts: 105
 Hi Theo,

I tested your PNG logo in Windows PageStream against the green background I was using to see if the transparent areas were truely transparent, or if they affecte the background.

When placing your PNG on top of the green background I thought I could notice a difference in the green background as showing through the PNG's transparent areas and outside it. I rendered a bitmap from PageStream and loaded it into ImageFX to test the RGB values inside and outside the PNG's "zone".

Outside the PNG zone:
R: 48, G: 92, B: 00

Inside the PNG zone (transparent areas tested):
R: 48, G: 91, B: 00

A very faint difference, admittedly, but it shouldn't happen at all in a professional desktop publishing program.

I've uploaded crops of these problematic PageStream renderings to PostImage.org. Unfortunately, PostImage adds JPEG compression to the images, but the difference may still be visible (it is very faint to being with):

Theo's logo:
http://s22.postimg.org/lfqcstbn5/test1.jpg


My PNG image:

http://s28.postimg.org/5eefcjtod/test2.jpg


I'm getting one bit(?) of difference in both by Red and Blue channels, whereas with your PNG only the Green channel is affected.


I'm preparing audio CD packaging for duplication. I'd prefer to use PageStream but why should I live with a slight difference in background colours when other software (like Inkscape) renders PNG transparencly properly?  The software should just do the job properly.  I hope this gets fixed.

Brent
2014-11-03 18:27:39 CT #9
T.J. Zweers
From: Netherlands
Registered: 2006-02-07
Posts: 331
Okay, that is looking for troubles, placing it as a jpeg. ;-)
Jpegs deleting as much colors as possible and has an 8 x 8 pixel block boundary.

Eh, I don't see those boundaries (although at the right side of each characters, I seeee something).
Furthermore I don't see anything worthwhile noticing.

So I load it in Lightroom, and I increased the highlights. And I see the boundary at the top of the png. Further I see nothing extraordinary.
I load it in, a very old, Paint Shop and looking with the pipet, and I see (no I notice!) a small differences between the green inside the png and outside (like you say).

So, yes, you convinced me that there is a difference.
This fault shouldn't be there, but it doesn't bother me that much. If I'll be bothered it will be the outline boundary of the png at the top.

Eh, maybe we convince Deron te give us, no let us buy, PGS 6. ;-)
I have some things I like to add in the new version.

Theo

woodenflutes@yahoo.ca [PageStreamSupport] schreef op 3-11-2014 om 18:01:
Hi Theo,

I tested your PNG logo in Windows PageStream against the green background I was using to see if the transparent areas were truely transparent, or if they affecte the background.

When placing your PNG on top of the green background I thought I could notice a difference in the green background as showing through the PNG's transparent areas and outside it. I rendered a bitmap from PageStream and loaded it into ImageFX to test the RGB values inside and outside the PNG's "zone".

Outside the PNG zone:
R: 48, G: 92, B: 00

Inside the PNG zone (transparent areas tested):
R: 48, G: 91, B: 00

A very faint difference, admittedly, but it shouldn't happen at all in a professional desktop publishing program.

I've uploaded crops of these problematic PageStream renderings to PostImage.org. Unfortunately, PostImage adds JPEG compression to the images, but the difference may still be visible (it is very faint to being with):

Theo's logo:
http://s22.postimg.org/lfqcstbn5/test1.jpg


My PNG image:

http://s28.postimg.org/5eefcjtod/test2.jpg


I'm getting one bit(?) of difference in both by Red and Blue channels, whereas with your PNG only the Green channel is affected.


I'm preparing audio CD packaging for duplication. I'd prefer to use PageStream but why should I live with a slight difference in background colours when other software (like Inkscape) renders PNG transparencly properly?  The software should just do the job properly.  I hope this gets fixed.

Brent 


-- 
Redacteur, vertaler, illustrator bij Ligfiets.net
2014-11-03 20:40:04 CT #10
wurzel
From: Unknown
Registered: 2000-05-27
Posts: 96

Hi woodenflutes@yahoo.ca,

I still use my miggy but have PGS 4 & 5 there, plus PGS 5 on Windows.

Perhaps send me the graphic plus rendered image & I'll see if I can pick anything up?

Curious myself.


On 02/11/2014, you wrote:
> Hi,

> I created some transparent PNGs in ImageFX on the Amiga. I used a true black R:0 G:0 B:0 to
> denote the transparent areas.

> When loaded into PageStream (latest version for Windows) it looked good. The transparent
> areas of the PNG seemed transparent and I could see the background (which was a solid
> colour).

> After rendering the completed work to a bitmap, I noticed a very faint difference between
> the solid green background of my work, and the solid green background showing through the
> transparent areas of the PNG image. The difference was VERY faint, but I could see it.
> Going back to the original PageStream document I took a good look and could see this
> difference too.

> I loaded the rendered image into ImageFX and used it to identify the RGB values of the
> green background in the transparent areas of the PNG and outside it:

> Outside PNG (correct background RGB): R:048, G:092, B:000
> Showing through the transparent areas of the PNG: R:047, G:091, B:000

> So there appears to be a math error in calculating the colour of tranparent areas in PNG
> images within PageStream. Maybe it is counting from 0 to 255 whereas it should be counting
> from 1-256?

> Anyway, it's not a hugely noticable thing, but it really bugs me.

> Loading the same PNG into Inkscape, with the same green background, worked properly, there
> was absolutely no difference between the green background and the background showing
> through the PNGs transparent areas.

> I can provide my original PageStream document or PNG if anybody needs to do a test.
>


Bye for now,
--
Russell

Very few profundities can be expressed in 57 chara

weather:
Partly Cloudy : 10.00 C, 50.00 F
Winds : South-west 18.41 MPH, 29.63 KPH, 16.00 Knots
Jersey Airport (EGJJ), United Kingdom


2014-11-04 05:01:34 CT #11
Brent W. Santin
From: Canada
Registered: 2007-11-02
Posts: 105
 Hi again Theo,

Glad you were able to see the effect "transparent" areas of PNGs have on backgrounds.  Yes, the colour difference occurs at the boundary of the PNG (usually the rectangular transparent area surrounding the visible part of your PNG).

If anyone wants to replicate this problem, do the following:

- create a new PageStream document and using the shape tools make a large rectangle and fill it with a solid colour to serve as a background (Object menu / Line and Fill).

- load a PNG with a 100% transparent background into PageStream and place it on top of the solid shape.

- at this point, if you look closely at the PNGs boundaries (the rectangle that defines the PNG's pixel borders) you might be able to notice a very faint difference in colour. I didn't notice this difference right away. Only after  examining the on-screen image closely and moving my head around (LED monitors look different at different angles) did it become apparent.

- in order to confirm what you are seeing, render out the document as a bitmap.

- load the bitmap into an image manipulation program that allows you to test areas of colour for their RGB values.  I use ImageFX's "pick" tool in the Palette window.  Other programs (i.e. Photoshop(?) might have an eyedropper or pipette tool).

- test the background solid colour both within and outside the PNGs rectangular border using the aforementioned tool.

- You will notice that in at least one colour channel, the values inside the PNG's rectangular boundary are different than on the outside (which is the proper colour). Usually this difference is a value of 1 lower than it should be.

- If you are having trouble seeing the difference, perhaps increasing the contrast, using an edge detection tool, or using a fill/flood tool with a tolerance of "0" or "1" will help define the different areas of colour.

Again, because the difference is so faint, it's not a huge deal, but the fact is that it should not occur at all.  It might be acceptable for hobby / amateur projects, but is not really acceptable for more critical projects. Plus, if an image generated by PageStream were to be post-processed by some other piece of software (i.e. sharpened, brightness effects) this colour boundary might become accentuated.

Does Deron read these messages?  Is it worth filling out a bug report?

Brent
2014-11-04 16:12:22 CT #12
T.J. Zweers
From: Netherlands
Registered: 2006-02-07
Posts: 331
Oh, yes, he does.
But an update? No, I don't think so.

Theo - hope I am wrong (about updates)

woodenflutes@yahoo.ca [PageStreamSupport] schreef op 4-11-2014 om 14:01:


-- 
Redacteur, vertaler, illustrator bij Ligfiets.net
2014-11-06 12:35:06 CT #13
Deron Kazmaier
From: United States
Registered: 2006-01-29
Posts: 4639

I was able to reproduce this problem, but I don't have a solution yet.
What platform are you using?

The real problem is that current PageStream is a work in progress trying
to get a Cocoa compatible Mac version out...

Deron


>
> Hi,
>
> I created some transparent PNGs in ImageFX on the Amiga. I used a true
> black R:0 G:0 B:0 to denote the transparent areas.
>
> When loaded into PageStream (latest version for Windows) it looked
> good. The transparent areas of the PNG seemed transparent and I could
> see the background (which was a solid colour).
>
> After rendering the completed work to a bitmap, I noticed a very faint
> difference between the solid green background of my work, and the
> solid green background showing through the transparent areas of the
> PNG image. The difference was VERY faint, but I could see it. Going
> back to the original PageStream document I took a good look and could
> see this difference too.
>
> I loaded the rendered image into ImageFX and used it to identify the
> RGB values of the green background in the transparent areas of the PNG
> and outside it:
>
> Outside PNG (correct background RGB): R:048, G:092, B:000
> Showing through the transparent areas of the PNG: R:047, G:091, B:000
>
> So there appears to be a math error in calculating the colour of
> tranparent areas in PNG images within PageStream. Maybe it is
> counting from 0 to 255 whereas it should be counting from 1-256?
>
> Anyway, it's not a hugely noticable thing, but it really bugs me.
>
> Loading the same PNG into Inkscape, with the same green background,
> worked properly, there was absolutely no difference between the green
> background and the background showing through the PNGs transparent areas.
>
> I can provide my original PageStream document or PNG if anybody needs
> to do a test.

--
Deron Kazmaier - support@pagestream.org
Grasshopper LLC Publishing -http://www.pagestream.org
PageStream DTP for Amiga, Linux, Macintosh, and Windows


--
Deron Kazmaier - support@pagestream.org
Grasshopper LLC Publishing -http://www.pagestream.org
PageStream DTP for Amiga, Linux, Macintosh, and Windows
2014-11-07 05:14:55 CT #14
Brent W. Santin
From: Canada
Registered: 2007-11-02
Posts: 105
 Hi Deron,

In reponse to your question about what platform I am using, I am using the latest Windows version of PageStream (I am using WIndows XP SP3).  I can get you the exact version number of PageStream if you wish (just e-mail me) but I am currently booted into Linux and can't check at the moment.

Thanks very much for your response.

Brent
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