Hex color code changes after layer merge and flatten?

[YiChen C]

I have an assignmet calls for certain background color.  I cut out a subject and color filled background color #ece0d4, when I do layer merge or flatten, the color changes to #ede1d6.  If I don't do merge/flatten and just save as jpeg, the color changes to #ede0d7. I could not get the color I need! I cannot figure why. Can any one shine me some light? Thank you

[Test Screen Name]

Saving as JPEG always changes colour. It is designed that way, so expect it. If an assignment demands an exact colour in a JPEG it is impossible. 

[YiChen C]

Ok.. after many tries, I find a way to keep the background color to my choice. 

1. Making sure I work on sRGB profile from the beginning

2. Select and cut out the subject in a new layer (Ctrl+J)

3. Select subject again and Mask this layer

Somehow, if I just select the subject in its layer and mask it, the background color will change....

If I select the subject in a new layer and don't mask it again, the background color will change. (I thought the background color should apply if the subject is on transparant background, however, it is not doing so and I need to mask it again.)

I dont know why it is like this...but at least it works. maintain background color after layer merge