Image outline after resizing

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Marc_Foreman
Posts: 3
Joined: Wed Feb 16, 2011 10:53 am
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Hi,

I am having problems running a file through BatchPhoto. Unfortunately I have been unable to upload files as an attachment to this posting, so I have placed them onto our server at the following locations:

http://www.vrmarketing.com/imagebug.zip

I have tried to process "input image.tga" through BatchPhoto, having set Batchphoto to apply a resize transform to 512x2048 pixels, and write the resulting image to filename "output image.tga" (which I include here as an example of the output I am seeing).

However, when I open "output image.tga", there is a ghost outline of the original artwork extending around the edges of the rescaled image.

I believe this may be related to the way Batchphoto perceives alpha channels against a transparent background, as for some reason, although when I open "input image.tga" in Photoshop, it appears against a white (non transparent) background, Batchphoto shows it against a transparent background.

Similarly, I have found that if I manually process the "input image.tga" by opening a selection set based on the embedded alpha, the invert my selection and flood-fill it with white (essentially re-painting the background), when the updated image is processed, this problem goes away. Unfortunately, this solution doesn't work for me as there are some 25,000+ images to process and the thought of applying this procedure manually (or even via a photoshop script) makes it non-practical due to time constraints.

Can you offer any assistance in explaining why this problem is happening, and producing a fix for it within BatchPhoto?

Please note that I am using BatchPhoto version 2.6.2. I would be happy to upgrade to a later version, but I would first need confirmation that the later version does not display this problem, so I would be grateful if one of the BatchPhoto administrators/technicians would check the process for me and let me have the output to confirm.

Kind regards,

Marc Foreman
Technical Director
VR Marketing
Cosmin
Posts: 376
Joined: Sat May 16, 2009 11:35 am
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Hi Marc,

I can see the problem you are experiencing. Indeed the "ghost" around the image seems to be related to the alpha of the original image.

In my tests I tried to save your original TGA image as PNG and the resulting PNG did not had this problem. So try to save your images as PNG and let me know if it works for you.
Regards,
Mike Cosmin Unguru
Product Manager
Marc_Foreman
Posts: 3
Joined: Wed Feb 16, 2011 10:53 am
Contact:

Hi,

Sorry, but for business purposes we need to stay with the TGA format, as the software we are feeding these images to requires TGA formatted images with alpha channels as separate entities within the file, rather than premultiplied and combined with the pixel matrix itself as happens with PNG.

Since this is a reproducible issue, is there anything that can be done to schedule a fix for the problem? If so, I would be grateful if you could give me some idea of timescales.

Best regards,

Marc
Cosmin
Posts: 376
Joined: Sat May 16, 2009 11:35 am
Contact:

Hi Marc,

Unfortunately we are using a third party component to process the TGA files so we don't have direct control over every aspect. However we will try to find a fix for this problem for the next release of BatchPhoto, I will let you know when it will be available.
Regards,
Mike Cosmin Unguru
Product Manager
Marc_Foreman
Posts: 3
Joined: Wed Feb 16, 2011 10:53 am
Contact:

Thank you Cosmin,

We have been able to successfully create a workaround by introducing a script in Photoshop which clips the visible pixels outlining the items to conform to the alpha channel and this has circumvented the issue. However, I will arrange for an upgrade of BatchPhoto as soon as you have a fix available.

Best regards, and thank you again for your assistance,

Marc
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