Raster transparency colour

[MichalMuszynski]

I can't solve this problem. I have two georeferenced rasters but in both of them boundary are white and it looks like on screenshot beneath.

What I have to change/ set/ to make this white strip in the middle between two rasters 'unvisible'. In such primitive soft like MapInfo it's pretty easy but here... i don't have any idea.

I'm using ArcMap 10.2.1.

[JimCousins]

For best results, you should set the extent to clip the rasters as close as possible to the edge of the data, then under the symbology tab for the layer, set the background color (these are RGB) to R = 255 G=255 B=255 and use the color = null (the default).
I suggest altering the extent, because it appears there is a black line framing the white border.

[MichalMuszynski]

Hello. Thanks for reply. Your solution helped partially. THe white borders disappeared ,but now the raster is only in black and white.

[JimCousins]

Apologies for being vague. Perhaps the screenshot will help - I did not change from RGB. I changed the "Display Background Value" entry only.

Regards,
Jim

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[MichalMuszynski]

Thanks again ! Unfortunately I don't have RGB option in Symbology tab (probably because my raster is jpg , not geotiff?), but I handled in other way. Maybe it will be helpful for others.

In symbology tab choose Colormap, then click a frame with white colour and select "No color". That's all.

Regards,
Mike