Red and Blue swapped on jpeg import

[Skaven252]

I've occasionally created some tone-mapped pictures from multiple exposure brackets using the Luminance HDR program. But when I import the jpegs exported from Luminance to Xara, their Red and Blue channels appear to get swapped.

I can fix it by using a Live Effect. But why does this happen? Is there a way to losslessly avoid this before importing to Xara? Because Live Effects impose their own resolution limitations on the image.

Thanks!

[steve.ledger]

Hmm, I just installed the Windows 64bit version and cannot repeat the problem. The Luminance exported JPG file is imported into Designer Pro X just fine..

[Skaven252]

Hi, thanks for your reply.

Here's the original image I had this issue with:
http://www.futurecrew.com/skaven/sha...4_tonemap1.jpg
(1.5 MB)

The photo looks OK when viewed in the Windows image viewer, and GIMP 2.6 also opens it with the right colors. But try downloading that and importing it to Xara (I did it by just drag-dropping it to the canvas).

I just purchased Xara 2013 MX and the issue is there, but it also happens in Xara 6. I'm running mine under Windows 7 x64.

[steve.ledger]

Yep, your file looks wrong in Xara Designer..
In Faststone and IrfanView its fine, so a copy and paste from either works fine, also should be lossless as it's the uncompressed file in the memory that you're copy/pasting..

Was the original camera photo RAW or JPG?

[Skaven252]

The originals from the camera were JPGs, but several of them (3-5) are combined into one in Luminance, then the result is exported into a new JPG. If I open this JPG in GIMP and re-export it, the Red-Blue issue is fixed (but the lossy compression loses some data).

I'm just wondering why Xara imports this JPG wrong if the other programs I tried don't have this problem.

Uncompressed copy-paste helps avoid the problem, indeed, but it also makes the Xara project file huge. Alas.

[ad1066]

I can confirm I am having the issue as well. The picture looks normal when opened in Windows Picture Viewer, but when imported to Xara Designer Pro X, the houses are blue and the sky is copper.

Furthermore, in Paint Shop Pro X3, the preview looks fine in the Open File dialog box, but the image shows up as a black rectangle when actually opened. MS Paint opens it just fine, as does Paint.Net.

-- Ben

[Skaven252]

Thanks for testing this.

When opening the .jpg in GIMP, it gives a dialog about an embedded color profile. Not sure if it's related, but maybe.

[steve.ledger]

Try saving from Luminance as TIFF or PNG. How is it then?
And which camera shot the originals?

[Luke.Hart]

The JPEG that Luminance creates is very unusual, instead of encoding each pixel in YCbCr, it uses RGB. The library we use to decompress automatically converts from the JPEG component ordering (BGR) to the windows component ordering when loading a YCbCr. When loading a RGB JPEG this conversion doesn't happen. By detecting RGB encoded JPEGs and doing the conversion ourselves, I have been able to fix this issue.

[handrawn]

Hi Luke

certainly something unusual in that JPEG - when I had it loaded in XDPX, Photoshop refused to start - I did some testing to ensure it was not just coincidence, but it was pretty certain... no problem loading the JPEG into photoshop if it was not already loaded in XDPX - don't know if that is any way helpful, or not....