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Cayman Diver II - More Photoshop Tips and Tricks

Discussion in 'Darkroom Tutorials' started by PapaBob, Dec 2, 2006.

  1. PapaBob

    PapaBob ScubaBoard Supporter ScubaBoard Supporter

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    I will start by thanking Cayman Diver once again for posting a great image to illustrate correction techniques for underwater images. All of the copyrights to this image belong to him. After posting my tutorial, I worked with the image some more and had a few alternative techniques I wanted to share with my Scubaboard Photoshop friends. If you have not looked at the original Cayman Diver tutorial, I suggest you review it. CLICK HERE FOR ORIGINAL TUTORIAL.

    I will be building upon it here. The goal, as with the original tutorial, is to make adjustments without complicated masks. No masks were created in this tutorial. We also want to use adjustment layers instead of adjustments on layers. I killed as few pixels as possible in the creation of this tutorial.

    For reference, this was Cayman Diver’s original image.

    [​IMG]
     
  2. PapaBob

    PapaBob ScubaBoard Supporter ScubaBoard Supporter

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    In the first tutorial I examined each of the individual color channels in Red, Green, and Blue. Red was dead, Green had most of the detail, and Blue had detail but was washed out. I started with replacing the Red Channel. I used the basic Mandrake action to do so. Actions are nice because you click a button and let the computer do the work. There is no doubt that the Mandrake Method is the most useful action for UW pics. However, what you get is what you get. When I ran a basic Mandrake I found red artifacts in the sand and on the diver. Yes, they were removed in Levels but I did not want them there to start. You have a lot more control in repairing a dead Red Channel if you use a Channel Mixer Adjustment Layer.

    With a copy of the original image as the background layer, click on the Adjustment Layer icon at the bottom of the Layers Palette (half black - half white circle) and select “Channel Mixer” from the drop down menu. This creates an Adjustment Layer above the background layer and opens a dialogue box initially set to the Red Channel with the red slider at 100%. I didn’t want any Red Channel information so I dropped the red slider to zero. The detail is in the Green Channel so I boosted the green slider to 70% and added a smidge of blue (4%) which produced a pleasing adjustment without red artifacts. You can watch the screen as you play with the sliders and stop before you introduce red artifacts. The fun with an Adjustment Layer is that you can go back and reset your settings at any time and you have not yet killed any pixels. This is a screen shot of my Channel Mixer Adjustment Layer settings and resulting image.



    [​IMG]
     
  3. PapaBob

    PapaBob ScubaBoard Supporter ScubaBoard Supporter

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    The next step was to color correct in Levels just like in the original tutorial. Once again, you work the red, green, and blue channels individually. By creating another adjustment layer, I did not kill any pixels (save the pixels!) and created the option of going back to the Levels Adjustment Layer to tweak it. The following are my Levels settings and resulting image.

    [​IMG]
     
  4. PapaBob

    PapaBob ScubaBoard Supporter ScubaBoard Supporter

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    You may recall that I used a Hue/Saturation Adjustment Layer to remove blue and cyan from the sand. I decided to do that again and this screen shot shows my settings and the results.



    [​IMG]
     
  5. PapaBob

    PapaBob ScubaBoard Supporter ScubaBoard Supporter

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    Golly, after three Adjustment Layers, the image has lost detail. In the initial tutorial, I made no attempt to replace it. Sharpening would not have worked because it only enhances exiting detail and does not replace lost detail. Instead, I started my detail restoration with a neat Photoshop trick.

    Photoshop pros use the Channel Mixer with the “Monochrome” box checked to create highly detailed black and white conversions. This works better than converting to grayscale or using the Desaturate function because you have much more control over the end result. We can use this method, not to create a super black and white image (although you can do that if you want), but to create an image with great detail we can use to restore detail lost as a result of color correction. Here is how it works.

    Click on the bottom (background) layer containing the original image and duplicate the layer (Ctrl-J). Take the background copy layer of the original image and click-hold-drag it to the top of the layer stack so it is the top layer. Your screen image should now look like it has reverted to the original image. We will fix that in a moment.

    With the top layer (background copy) active, create a Channel Mixer Adjustment Layer above it. Click the “Monochrome” box in the lower left of the dialogue box. Wow, everything just went black and white. We now want to use the red, green and blue sliders to create the perfect detailed black and white image. The Red Channel has bad info so we will reduce its contribution to zero. Most of the detail is in the Green Channel so we will boost that way up. Add a smidge of blue and we are finished. These were my settings and the resulting image. Your eye may have produced something different.

    [​IMG]


    We now want to merge the Channel Mixer Adjustment Layer into the background copy. After clicking OK to accept your Channel Mixer adjustments hit Ctrl-E. This will merge the Channel Mixer Adjustment Layer down into the background copy. Your screen should still show the black and white image and the Layers Palette should show the top layer as the same single black and white image.

    Now the magic. The black and white top layer you have just created has all the image detail you lost in the color correction process. If you change the blend mode of the top layer from Normal to Luminosity it will use the image detail in your perfect black and white top layer and blend it with the color in the layers below. Detail restored with color correction. Yes, you can have your cake...
     
  6. PapaBob

    PapaBob ScubaBoard Supporter ScubaBoard Supporter

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    I renamed the layers for identification but this is what my Layers Palette looked like after the above steps and the resulting image.

    [​IMG]
     
  7. PapaBob

    PapaBob ScubaBoard Supporter ScubaBoard Supporter

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    Lets review the results of the forgoing steps in RGB color mode before we go on.

    This was the original image

    [​IMG]

    This was the image after the Channel Mixer Adjustment Layer

    [​IMG]

    And after the Levels Adjustment

    [​IMG]

    And after the Hue Saturation Adjustment

    [​IMG]

    This was my Channel Mixer black and white.

    [​IMG]

    And the result after applying the detail in Luminosity mode.

    [​IMG]
     
  8. PapaBob

    PapaBob ScubaBoard Supporter ScubaBoard Supporter

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    In the original tutorial, I did not stop there. I had to try some more tricks in the Lab color space. If you have been following along, create a duplicate image (not a new layer but a duplicate copy of the image you have been working on) Keep your original RGB working image open (we will need that black and white layer). In the duplicate, click the eyeball icon on the black and white luminosity (top) layer off to hide the black and white layer or discard the layer entirely (your choice). Then flatten the image (Layer>Flatten Image). You should now have a single layer in the duplicate image that contains the results of our previous processing, except the detail we replaced with the discarded black and white layer. We are going to use a different detail replacement technique in Lab.

    In this phase we are going to restore the detail in Lab mode so convert the duplicate to Lab (Image>Mode>Lab).

    In the original tutorial I applied a contrast curve in the “L” channel and made adjustments to the “a” and the “b” channel. I am not going to do that here. The only adjustment will be a color enhancement in the “b” channel on a Curves Adjustment Layer and my settings and the resulting image are shown below.

    [​IMG]

    At this point I have to ask whether you like detail or contrast? It is cliche in photography that images thrive on contrast so in the original tutorial I applied a contrast curve to the “L” channel. My wife thinks that made the image “pop.” I agree. I am known for liking images on the high saturation, high contrast, side. You, however, may like more detail and less contrast. That is why, for this tutorial, I did not apply a contrast curve to the “L” channel in Lab and only made adjustments in the “b” channel. Here is how I replaced the lost detail from all of the RGB adjustments and the Lab conversion.
     
  9. PapaBob

    PapaBob ScubaBoard Supporter ScubaBoard Supporter

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    In the Lab image (now consisting of a background layer and the Curves Adjusment Layer) I wanted to “stamp” a composite layer. The command is Shift-Ctrl-Alt-N-E. This creates a layer above the background and Curves Adjustment Layer containing the information in both. Next, I go back to the original RGB project (remember, I duplicated the image before converting to Lab) and duplicated it again. Then, on the duplicate, change the blend mode of the B&W top layer back to “Normal” which will restore the black and white detail image you created. Flatten the image. Hit Ctrl-A to select the entire black and white image. Then Ctrl-C to copy it into the clipboard buffer. Then switch back to your Lab image and make sure the top (stamped) layer is active. Open the Channels Palette. Click on the “L” channel to make it active. Then Ctrl-V to copy the B&W image into the “L” Channel. You have now replaced the “L” Channel (which contains the detail information but no color information) with your “perfect” B&W.

    This is the “L” Channel before replacement.

    [​IMG]

    And after replacement.



    [​IMG]


    And the resulting image.


    [​IMG]
     
  10. PapaBob

    PapaBob ScubaBoard Supporter ScubaBoard Supporter

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    Another Photoshop pro trick. If you sharpen an image in RGB mode it often introduces halos and color shifts. Bad. So a lot of pros suggest converting to Lab and sharpening the “L” channel. I have a “have your cake and eat it too” wrinkle on this technique. Why not use the Shadow Highlights function in Lab to increase contrast and sharpen at the same time. With the layer set to the top layer in the Lab image, I clicked on the “L” channel in the Channels Palette to make it active and applied a Shadows Highlight adjustment with Amount 33 - Tonal Width - 37 and Radius - 11. This is the result.

    [​IMG]
     

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