Thanks! Do you know how much distance should be in place between subject and foreground? a ft , 2ft? or does it depend on the lens used?
I received the image as a raw file, uploaded on imgur and that was what it showed. The hoodie worn was quite bright, so it might just be that.
I cannot simply tell you how much distance, without knowing everything else about the shoot, but you can get that information by consulting a DOF calculator, which you can find online.
If you consider all the factors involved in producing blur (both background and foreground) you will see that distance from camera to subject is one factor, and distance from the subject (the part that is in focus) to the background is another factor.
To increase blur in the background, have the background farther away.
Yes, it does somewhat depend on the lens, because both focal length and aperture are involved.
You received this as a raw file. Did you do the photography yourself? Is this your photograph? Did your camera not generate a jpeg file as well? Most cameras will generate a jpeg, even one that is embedded within the Raw file so it becomes viewable. People cannot "see" a Raw file, so that is why there is a jpeg in it.
You have inferred that you had not seen the image until you uploaded it to imgur. Did I understand you correctly? How did you acquire the raw file?
If the highly-saturated yellow color of the garment was simply that bright, why are not all colors equally as saturated? In other words, the other colors in the photograph are somewhat muted compared to the yellow.