Studio backgrounds can be a pain in the butt. They get wrinkled, they're hard to roll in and out and they get easily dirty.
Does anybody know a good technique (or tutorial) on how to clean them in Photoshop quickly with good results?
I've been using the brush tool to paint over them but this gives a boring Photoshop look to it. Using the clone stamp on the other hand is tedious and doesn't give good results either.
I've done a lot of this work in the past and tried enough different methods to be sure that there is no quick way to do it that gives good results. You can have either quick or good, but not both together. I'd love to be proven wrong on this as I imagine I'll have to do a lot more of this work in future.
Here are the three main methods I use:
Manually cut out the subject (with the pen tool, lasso etc.), fill the outside area with white. This is the most time consuming but provides the best results. Works best with head/torso shots as if you're working on a full length shot this method removes shadows which prevent the subject being grounded (they look like they're floating in the air). Hair is very problematic so I often rely on the below method for the hair.
Blowing out the background, i.e increasing brightness contrast until the background goes pure white. This can be done globally if you're lucky, but most of the time the background brightness will shift across your image (due to shadows / light falloff), so the amount of brightening to blow it out will vary. I work around the subject with a selection along the edge of the subject, fading out gently into the subject, and adjust the curves until the background goes white locally, then move the selection on to the next part of the edge. Downsides of this method are that it is still time consuming, can produce artifacts / colour shifts in the edges of the subject, and it only works if the background is fairly bright / even to begin with. Also it can't handle shadows.
Blurring the background. Blurring evens out creases well, and copes with shadows and changes in background brightness. The problem with this method is you can't get too close to your subject(s) without blurring them, so you can blur the large areas but then you often need to do some manual fixing around the edges of the subjects using the above methods.
I know your question specifies "in photoshop", but it really does bear repeating that if you can get this right in-camera you can save a load of work in post. (Obviously, you know this!) I have found this out the hard way :(
I'll have a stab at a few suggestions to help get this right in-camera:
I'll leave it to others to add any other tips (community wiki).
I realise that this might not answer your question, nor solve your immediate problem, but it does help to make the site more complete for people researching the problem of getting the background right.
Dust and Scratches Filter
For dirt and smudges, if your background is untextured you can use Filter > Noise > Dust and Scratches. This will remove any defects, of any size you choose, in one go. I would make a rough selection of the background, put into a new layer, run the dust and scratches filter. Then you have the ability to use a mask if you want to be more selective about where you apply, and don't apply, the effect. If you make the layer a smart object you can revise the filter settings if you have over- or under-done the filtering.
Healing and Patching
For larger patches, use the healing tools (particularly the patch tool). Select an area with a defect, then drag that to a good area. Photoshop will fill the defective area with something that has nice texture and color.
An alternative is to select an area that is good (no defects) and duplicate that into a new layer. Move that over the area that has problems. Cover the new layer with a black mask, then paint in with white, at low opacity, where you want to cover up the defects. This means you end up with all texture and light variations, rather than painting a solid color that will look artificial. You'll need to use an area that closely matches the color and brightness (or apply a levels/curves adjustment to make it match)
Content-Aware
Another simple method is to select an area, then Edit > Fill and select Content-Aware. This will remove the defect and attempt to match color, brightness and texture from surrounding areas. This works well in the interior, but may have problems near edges.
If you have wrinkles or folds that are not close to the subject, you can use content-aware scaling to stretch the background (leaving the subject unaltered) so that the areas containing the defects are dragged out of frame.
If you are shooting from the same perspective a lot, so that the defects are in the same position, you can create a mask in photoshop to cover them up, then for future shots, you can create a new layer and reuse this mask, adjusting the new masked layer each time without having to find the defects and figure out a way to cover them over and over again.
Quickly:
Select background roughly (via eyedrop+similar or with a lasso tool)
Feather selection enough to correct only background.
Apply levels and/or blur to clean background. Experience here to find best results.
Correct minor details with clone stamp with little brush and huge feather.
Between steps 2 and 3 you can hit CTRL-SHIFT-H to hide selection and helps to see if you made a good selection to start applying the corrections.
That's my way. Sure there are anothers. Hope it helps.
As mentioned above. The best thing is to use a clean backdrop. Sometimes I don't have control over the backdrop at all. I use a mix of content-aware, patch tool and spot healing brush tool to clear any marks on the backdrops.
Here is few simple steps
Steps are given in following video : https://www.youtube.com/watch?v=BdDYvbx6SC0
