Gray background when encoding JPEG2000 mosaic from grayscale

[vindaloo]

Using GeoExp7 to create JPEG2000 files from tiled TIF's. Unfortunately, it gives my images an unwanted dark gray background. But, using GeoExp7 to create SID files from the same TIF's gives an image with a nice white background, just like on the input tif's. When I run the mosaic encode in GeoExp7 for either output formats JP2 and SID, it says of the input TIFs, mosiac width 14172, height 14172 pix, size 191 MB, type TIFF, Grayscale(1 band), input sample type 1 bit/sample unsigned. For both ouput formats, I set Encode ratio 10:1, Lossless is unchecked, Encode as test image is checked.
I've been successfully encoding lots of stuff into JP2 thru GeoExp7 but I have 16 maps of these tiled TIFFs that give the nasty dark grey background.

It was suggested that I select a different background color via the more encode options and background color. When I go to that screen it says "BAND = GRAY" & "VALUE = <Blank>". I've tried VALUE = 0 for encoding a JPG2000. But the resultant image still had a dark grey background. In another attempt a VALUE of 1 produced a totally grey image, with no foreground data (ie absolutely no use).

So to recap, if I encode a set of TIFF tiles thru for a SID the background is a desirable white. If I encode the exact same TIFFs thru for a jp2 the background is nasty dark grey. Any ideas how I make a jp2 with white background?

Product = GeoExpress Standalone
Version = 7.0.0.2052 HEAD
Operating System = WinXP 2002 sp3
Ram = 2 gb
Drive Space = 120 gb free

[rparker]

Hello,

What happens if you try a lossless encode to JPEG 2000?

What happens if you set both background and transparency values to 255?

[vindaloo]

I haven't had a chance try out your suggestion, yet.
Will let you know if it cures the problem.

[vindaloo]

Just tried both of your suggestions. But, unfortunately it didn't provide a fix.

First, I created a jpeg2000 mosaic from a few of my tifs, with LOSSLESS ENCODE checked. The background was still dark gray.

Then, I created another jp2 file with both BACKGROUND set to 255 and TRANSPARENCY set to 255. Again, the background was still dark grey.

Can I send you an example .TIF for your company to do some tests?