getting rid of this purple mark on old photo

[xinvux]

Hi, i'm new to photoshopping old photos. i am trying to retouch an old photo and am stuck at this point:
there are some kind of purple/blue-ish patches all over the photo, (see attached image) how do i go about getting rid of it?

any help is greatly appreciated!!
thanks in advance!

[Chain]

Red channel seems fine. It is limited to the green and blue channel (blue channel looks fairly messed up).

I was first thinking to use the green channel to replace all or parts of the blue channel, but I don't know how bad the colour shift would affect the rest of the image. And since some of it is in the green channel it won't be enough to remove it (and it will still look bright).

2nd thing I tried was selective colour. Adjusting the blue, cyan and magenta channels. It did reduce, but not remove it. Definitely an improvement, and worth a try.

Perhaps combine both methods? I've seen this type of "stain" before; but I have no experience in removing it. Anyone else?

[Tony W]

This is a difficult one to do and look good partly due to the pixel artefacting as well as the staining damage. It could be due to image size restrictions on the forum or a less than optimum scan of the original.

Assuming that this is a scan from an old print what size is the original and what settings did you use for the scan process?

If this is the best scan you can get then you are somewhat limited with what you can do with the image IMO. As Chain said the Red Channel is ok but the green and blue are damaged too much - a better scan may help but I just do not know.

Anyway a quick play came up with the following:

• First applied Curves to 'improve' the image a little
• Add Hue & Sat layer and selecting the stain area completely desaturated the magenta and blue components. Leaving the stains looking neutral
• On a new layer used the Brush tool (opacity approx 40%) and Color mode set selected a colour close to damaged area and painted over. Also alternated between Color mode and Luminosity for the brush to attempt match between density and colour

TBH, it still looks perfectly dreadful to me and unless I could get a better scan then I would be inclined to write this one off
EDIT: Going to add something and managed to delete image so reloaded

[lurch]

See http://www.retouchpro.com/forums/pho...silvering.html

[xinvux]

Originally Posted by Tony W

Assuming that this is a scan from an old print what size is the original and what settings did you use for the scan process?

the original scan is 1050x1044px 300dpi, what i uploaded is a part of the scan and due to the size limitation on this forum, i had to reduce the size.

anyways, i will give your and Chain's suggestions a try!

Thanks for your help!!

[Lou R]

Another way (there are several, actually) to fix this is to recolor the damage.
Select the color of the area to be recolored. Depending on whether the blue is lighter or darker, set your paintbrush on lighten or darken and about 40% opacity and carefully color in the marks. This works best with a tablet if you have access to one. For sharp edges, like the edges of the table, you may want to use a selection tool to mask off what you don't want recolored.

[Tony W]

I appreciate that it is only part of the scan due to limitations of downloading. Are you saying that your original scan of the whole image came out at 1050x1044 pixels as that would make the actual original around 3.5" square? Or do you mean just the section?

I would be tempted to scan again at a much higher resolution than 300ppi (assuming your scanner supports it) - it may just be helpful in recovering useable info. I would also try and optimise the individual channel detail using the scanner software making sure not to clip the RGB channels prior to bringing into PS

[xinvux]

yes, the original scan of the whole image is 1050x1044px. i will have to check if my scanner allows me to scan higher than 300dpi.

thanks alot for your suggestions!

[Tony W]

I cannot guarantee but I hope that a higher resolution scan may help recover the maximum information (including the damage) but be aware that there comes a point when increasing ppi does not actually gain anything in resolving extra detail on the print.

So if you go too far you will suceed in uneccessarily increasing file size without any advantage in gaining additional detail. I would try if possible a couple of scans at increasing levels e.g. 600ppi and 1200ppi and compare to see if you are getting any more info.

Higher resolution scans than normal for prints can be useful to help deal with damaged areas more effectively.

[xinvux]

Originally Posted by lurch

See http://www.retouchpro.com/forums/pho...silvering.html

thanks for the tutorial lurch! i will give this a try as well.

Tony W, thanks for the advice, I will keep that in mind.

[edbayani]

go to channels and even out the blotches on all channels and toggle between the RGB and the channel you're correcting