Blotchy areas on gray seamless

[tatertodd007]

hey guys!


been shooting some product work and shot for the first time on gray seamless. I noticed after shooting the seamless looked blotchy/almost pixelated in certain parts. viewing the raw file in both photoshop and lightroom showed the same thing. wondering what the easiest and fastest way to clean this up.

thanks in advance!

 

[IamSam]

Hello and welcome to PSG>

Honestly, I'm not seeing it. Could be a lighting problem during the shoot.


But, yoo can make a general feathered selection of the BG and add a blur.

 

[tatertodd007]

thanks I just found this site! I'm terrible with photoshop so this place is wealth of knowledge!

you not seeing it makes me think its probably just my monitor and this will be printed so that doesn't matter. ill make some prints and see

thanks again!!

 

[Tom Mann]

Could u post a cropped & magnified view of a problematical area? That would help.

Tom M

PS - welcome !!!!

 

[tatertodd007]

the blur seems to have cleared it up

 

[BaluM]

May be its resolution issues ??

 

[peta62]

What I see there is the background goes from almost focused to totally out of focus, so it can be bokeh issue. I would, aside of Photoshop manipulation, put the background far back and perpendicularly to the direction of your shot.

 

[tatertodd007]

awesome thanks for the tip. I've managed to get it looking pretty good for print. and the shoot is over so no going back, I'll learn from my mistakes. appreciate the advice.

 

[Tom Mann]

Just a word of caution about using blur to work around problems like this: In the experience of many photographers, adding even a small artificial blur can be disconcerting. This is because it doesn't give your eyes something to focus on. It also can scream, "Photoshopped!" to the world, LOL.

So, after blurring, many photographers will add back in a small amount of relatively hard edged grain to make it look like the background is in focus and hasn't been manipulated.

Tom M

PS - tatertodd007, I couldn't tell if the last image you posted (i.e., the cropped one) was before or after blurring. I asked for a "before" shot, but from your comment, "...the blur seems to have cleared it up...", it sounds like it was after blurring. Which was it?

 

[tatertodd007]

oh sorry! that was from before I did the blur.

 

[Tom Mann]

To be honest, I'm not sure what caused the blotchy look, nor what caused the profound difference in the character of the noise in a strip across the bottom of the frame, but the classic way to get rid of this sort of blotchy look is to work in the Fourier (spatial frequency) domain and greatly reduce the low and middle spatial frequency components of the gray background, leaving the high spatial frequencies alone, or even adding in (as I mentioned before) a bit of well behaved noise to give the eye something to focus on.

Fortunately, since the introduction of Topaz Detail, performing this mathematical task has become as easy as pushing some sliders around, e.g.:


View attachment 61812

After this step, using the "Film Grain" part of NIK Color Efx Pro package, I then added back in a bit of nicely uniform grain.

I also noticed that there appeared to be a noticeable amount of camera shake present, so I used the anti-shake tool present in the last few versions of PS CC to help this along.

Attached below is a 1:1 crop from your first posting turned into an animated GIF showing before (blurry blobs) and after versions.

Also attached is a non-animated version that's the same size as what you first posted. Be sure to click on the in-line preview to see it at its full rez.

HTH,

Tom M

PS - Thanks for posting the crop. Unfortunately, it didn't help all that much

PPS - The cause of the blobby look has me really puzzled, so one question: What processing did you do to the 1st image (other than cropping) before you posted it here?

 

[Tom Mann]

@OP - I just re-read your first post and noticed that you started with the raw file for this image. I'm really interested in learning what caused the blobby look, so is there any chance you might post the raw file?

To do this, you have to fool the forum uploading software by zipping the raw file, and then posting the zip file just like you would post any ordinary image file. The uploader will give you a warning saying that it doesn't recognize that file type, but just ignore it and forge ahead, and it should upload without problem. If you are uncomfortable posting the raw file publicly, you could also use either Dropbox or YouSendIt.com to get it to me. (Just send me the link in a PM).

My guess is that you don't want to run into this again, so if I can figure out what caused this, it will satisfy my curiosity as well as help you in future shoots of this type.

Cheers,

Tom M

 

[peta62]

Tom Mann - there are two reasons in my opinion :

1 - as I wrote in #7, it is how the structured material goes gradually from fully focused, but under sharp angle ( lies under the photographed object ) to way out of focus perpendicular ( vertically hanging background )
2 - it seems to have different angle and maybe even intensity of light - upper part having less light, whether due to lighting or reflection.

I think both these aspects cause different structure and noise.

 

[tatertodd007]

thanks for all the help and advice guys! Ive seem to have corrected the problem but will definitely take your advice for the next shoot. I hate doing things in post so it seems I need to pay more attention when I shoot. live and learn. thanks again guys much appreciated

 

[Tom Mann]

tatertodd007 - What about my request about sending me the raw file so I can investigate further?

Tom M

 

[tatertodd007]

I'm not at home at the moment but I will when I am

 

[Tom Mann]

I'm not at home at the moment but I will when I am

That's great. Thank you. I'm not at all convinced that the background being OOF (which it is) is the only culprit here. I have used gray / blue / etc. muslin backgrounds for decades and don't see this effect.

I suspect that something was done to increase the local contrast (eg, the clarity control in ACR was used too aggressively, or something similar) that brought out this blotchy pattern.

Tom M

 

[peta62]

Tom Mann - not because it is out of focus but because it spreads the area from focused to out of focus, so it may play with bokeh and change its pattern ( it seems more like a carpet than muslin background ), also aliasing may be involved, especially if the upper part has some angle.

 

[Tom Mann]

peta62 - Hey Pete, I think we are each addressing the problems in two different areas of the image.

I think your explanation for what happened in area "A" is right on the mark, possibly assisted by some extreme settings in the OP's raw converter, whereas my comments were mostly about why the worm-like artifacts are so visible in area "B". In using cloth backdrops for many years, the usual patterns in the backdrop that I have to deal with never look like these, but almost always are caused by residual fold marks / creases from storing the backdrop in a duffel bag and not taking time to get rid of them by either letting it hang, toss it in the dryer, or even better press it with a steam iron.

Tom M

PS - BTW, in the attached image, I cranked the contrast *WAY* up to make the differences in patterns in the two areas more visible, especially when viewed on a cell phone or similar small screen.

 

[peta62]

Tom Mann - yes, you are right, I looked mainly at A, where it steeply runs through different focus zones. I also strongly agree so in A as B are probably some extreme Camera Raw settings. I do not know whether you agree, but I also think area B is ( aside of Camera Raw settings ) probably affected by the carpet-like texture of the background and some type of aliasing ( that texture with chip dots ).
Peter