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OPR Workshop Information Exchange => Photoshop Discussion => Topic started by: G3User on November 23, 2010, 02:23:58 AM

Title: Curves
Post by: G3User on November 23, 2010, 02:23:58 AM
I use CS3 and usually add a levels layer above any restoration with the mid control set to 1.2 or thereabouts, it helps to make damage more visible.
 I donít remember where I saw this method of using a curves layer to emphasize even quite small changes in luminosity but it is simple to do and you can do some repairs while it is on.
The Curves layer looks something like this, I just grab the curve and lift it up and down to get what I called a zig zag Hannie.  I have saved it and have been putting it above the levels layer.
(http://i151.photobucket.com/albums/s145/atholg/curves.jpg)

With it showing over the original image the view is something like this.
(http://i151.photobucket.com/albums/s145/atholg/example-1.jpg)

Because the contrast is so high and the colour so bright, you can clearly see the damaged areas. It also gives you another view as an alternative to channels.
I have been using it to check my restorations but have found you can do some repairs with it on. The healing brush, smudge and blur tools can be used freely. The clone stamp tool in normal mode will only work if you have identified source areas with undamaged colour. If there isnít an area with undamaged colour you can still do the luminosity/blending repair and correct the colour later in the normal way. The view is only showing luminosity changes, not hue and you have no way of judging hue with the curves layer on.
The view highlights one of the problems of using the healing brush if the sample point is not changed regularly. The regular pattern really stands out with this view of the repair. 
As a double check I found it useful to turn the levels layer on and off as well, this shifts the mid-tone luminosity sideways so that areas that were near the crest or bottom of the curves and didnít have the high contrast are moved to higher contrast areas.
Adding the curves layer also allows you to review repairs made in the normal view, I invariably find things that I have missed. It is very effective in checking shadow and highlight damage/detail where your monitor may be crushing and have damage which will only show up in a print.
As well as major damage, the wall behind the girl has random red damage and there are no areas suitable as a source for the clone tool. With the curves layer off, I pixel peeped and was able to create a patch on either side of her head to use as a clone tool source. Made the curve visible again and did the repair using clone stamp. The junction between the two repairs was very easy to see and was blended with the healing brush and low opacity clone stamp.
Her skin repairs were made with curves both on and off, her dress with it on and colour correction needs to be done on a separate layer.
I will be interested to hear if anyone else is using this approach or has any comments.
And this was supposed to be brief!

Athol
Title: Re: Curves
Post by: Hannie on November 23, 2010, 06:20:35 AM
Thanks Athol!

I remember those curves, I never got beyond using it for psychedelic art but I see that it can be very useful in restores.
http://www.operationphotorescue.org/forum/index.php/topic,2502.0.html (http://www.operationphotorescue.org/forum/index.php/topic,2502.0.html)
I will have to give it another try,

Hannie