sRGB conversion-do I need to assign a profile before uploading

[paullantz]

I know that smugmug converts things uploaded to sRGB if they are not already in sRGB.
Sometimes I have noticed photographs that on smugmug, viewed in IE, seem rather more vivid, more orange and red, than intended.
As an experiment today, I uploaded the same photograph twice, the first one as aRGB which got converted and one as sRBG.
http://paullantz.smugmug.com/gallery/770944_wNf3b#542749694_nM4Hw
http://paullantz.smugmug.com/gallery/770944_wNf3b#542064722_jSucd

I found that it seemed to help to assign a color profile explicitly (assign profile) in PS even when the file had been converted from RAM as sRGB, is this necessary to ensure that smugmug does not do its own conversion?
Picture shot in RAW, processed in ACR and PS/CS4.

[jfriend]

Your image, when uploaded, should have a profile in it. Ideally that profile should be sRGB, but if it's aRGB Smugmug will convert.

If you are uploading images that have no profile, then they are "mystery meat". Color-managed software that intends to use the profile to properly display your image has no idea how to treat your image - it's a mystery. So, they have to make guesses which will sometimes be right and sometimes wrong.

To add to this, some browsers are color-managed and some are not. Safari is always color-managed. IE is never color-managed. Firefox 3 is not color-managed by default, but color-management can be turned on.

Best practice is to make sure that your image is actually sRGB (convert to sRGB, never "assign" sRGB), make sure the sRGB profile is in your image when you upload it so that Smugmug can know what it really is, make sure your monitor is properly profiled by a hardware color profiler and make sure you use only color-managed applications (Photoshop, Lightroom, Firefox 3 with color-management turned on, Safari, etc...) to view your images.