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Processing tips and tricks.

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  • Processing tips and tricks.

    Following a set of instructions that I put together on how to create an "Action Set" to remove dust spots using PS CS3 it has been decided to create this Sticky thread for tips and tricks of digital processing.

    This thread is not to be used for general discussion and is only open to crew members to add to.

    If you have a tip or trick to offer then please post it in the Who needs help with their scans / rejects?? We can help you! forum. The crew will then move suitable items to this sticky thread.

    The Index starts here and will be updated as further tips are posted....

    1. How to create an "Action Set" in Photoshop to make dust spot removal easier. Slightly modified by Brian Whitelegg from a Jid Webb original work.
    2. A link to Paul Nichols' excellent guide to using the histogram.
    3. A link to Stefan Kuhn's excellent workflow guide. Also includes further links within Stefan's page to advice on Nikon D100, D200 and D300 useage. Downloadeable as a PDF file as well.
    4. Shadow/Highlight tool. How to avoid haloes (Overprocessed) rejections. (Updated 29th May with some example images)
    5. LCD monitor view angle calibration.
    6. A contrast tutorial by Paul Nichols. link removed for maintenance.
    7. Setting sRGB as your working colour space. (sRGB displays colour on the web more effectively than Adobe RGB)
    8. ------Removed-----
    9. The luminosity histogram.
    10. Edge halos, how to get rid of them. By Angelo Bufalino.
    11. DELETED AS NO LONGER VALID> Similar and 45 degrees advice.
    12. Centreing a picture. Simple diagram to explain.
    Last edited by brianw999; 2017-12-20, 12:40.
    If it 'ain't broken........ Don't try to mend it !

  • #2
    1. How to create an action set in PS CS3 (and might work in CS4/5 but not tested) to allow for easy dust spot removal. EDIT: 08/January/2018. Tested in Photoshop CC where it works just as well.

    Create an action set.
    To enable correction of multiple spots you can create an action set in CS3. (note. I don't use CS4 or CS5 but this is probably the same method in those versions)

    1. In CS3 open an image, any one will do.

    2. Press F9 to open the action palette.

    3. The menu for the action palette is in the top right of the new window just under the X that closes the palette. The same applies for the Layers palette that we will use shortly.
    Select "New Set" and name it. I used "Spots"

    4. Select "New Action" and name it. I used "Spots On". It will default to the Spots set. Leave this alone. For function Key select F2 and check the Control box. When you come to use the action you will switch it on by using Ctrl+F2. If you already use this key control set than select another option instead of Control. You can also select a colour for the button relating to this action but I tend not to use it. If you do select a colour it won't make any difference to what we are doing. (Actions can be accessed by opening the Actions palette and selecting the appropriate colour button. I find keyboard commands easier to use)

    From now on be careful. You are going to record the various actions and a mistake will ruin the action set. For clarity the following instructions are colour coded to indicate where you need to be to perform the function. Action palette menu are in red, PS CS3 menu are in blue and Layers palette menu are in green.

    5. From the action palette menu select "Start Recording". There's no rush, it won't time out.

    6. In the PS CS3 menu bar go to "Layer"..."Duplicate current layer" and create a background layer.

    7. In the PS CS3 menu bar go to "Image"..."Adjustments"..."Equalise".

    8. Press F7 to open the Layers palette. Select the Background Layer by clicking on it.

    9. Go to the Actions menu and stop recording.

    Now, still in the Actions menu select "New Action". Name this action "Spots Off". Set the function key to F2 but this time select the "Shift" check box. You will be using Shift+F2 to turn off the action set once you have fixed your spots.

    Start recording.

    10. Go to the "Layers" palette and select the "Background Copy"...NOT THE BACKGROUND LAYER THAT you previously selected.

    11. Still in the Layers palette menu select "delete layer"

    12 Go to the "Actions" palette menu and select "Stop Recording"

    .....and that's it. You have now created an action set that will be activated by Using Ctrl+F2. It will automatically equalise the image showing all spots, you can work on them without having to switch between equalised and unequalised for each spot and you can even use the selection tool to isolate those irritating little spots that appear on an edge in order to fix them without damaging another part of the image.
    Select the heal tool and heal over each spot, alternatively use the clone tool. These days I tend to use the clone tool by preference.

    One thing to note. You will be thinking "Sod it, it's not working" because you don't see any difference while working on the spots. The healing or cloning is being done out of sight on the background layer. When you close the action by using Shift+F2 you will see that the spots have been fixed.

    I've tested this and it seems to be working fine. Get back here if you have any problems.

    Finally, all the credit for this information must go to Jid Webb who first posted this information some time ago. I have merely copied and slightly modified it. Unfortunately the links to his workflow tutorial currently result in an "Error 404, access not permitted" message.
    Last edited by brianw999; 2018-01-08, 17:02.
    If it 'ain't broken........ Don't try to mend it !


    • #3

      Here's a link to an excellent guide to using the Histogram by Paul Nichols. This one is a "Must Read".
      Last edited by brianw999; 2011-09-08, 12:54.
      If it 'ain't broken........ Don't try to mend it !


      • #4
        3. A link to Stefan Kuhn's workflow guide.
        If it 'ain't broken........ Don't try to mend it !


        • #5

          Shadow/Highlight tool. How to avoid haloes (Overprocessed) rejections.

          Warning....Excessive use of Shadow/Highlight will make your image worse than it was in the first place.

          Shadow highlight is often used instead of the "Curves Adjustment" tool because Photoshop users have difficulty understanding how to use Curves. It is well worthwhile getting to know how to use Curves but in the meantime, here's how to avoid those horrible Haloes when using Shadow/Highlight.

          [NOTE: There is no replacement for a properly exposed image in the first place. Getting used to your camera and producing well exposed images in-camera will mean you shouldn't even need to read any further]

          Firstly...Crop to size (Those of you working to 1024 pixels may find it better to process at 1200-1400 pixels wide and then make a final resize), adjust the histogram (See Paul Nichols' tutorial on the histogram) and clean off any dustspots (See my dustspot removal tutorial).

          Here's an image before adjustment. I want to darken the roof to improve the contrast. (Ignore the spots...this is to show the process !)

          1. Go to "Layer"..."Duplicate Layer"...and click OK to "Background Layer"

          2. Go to "Image"..."Adjustments"..."Shadow/Highlight"

          3. The next window will default to 50% Shadow and 0% Highlights. You will see that shadows have become very light and also very grainy. 50% Shadow is far too high a setting for useable pictures due to the high level of grain. Any setting above 10% is too much.

          4. You can use the Highlight setting up to around 10% to darken a light fuselage and make it more contrasty against the sky. Again, any more than 10% is really too much so if the image needs more than these settings then you are probably better off binning this one and finding a better image to work on.

          [NOTE: Watch what happens when you make adjustments in the range 0% - 5%. The majority of useable changes happen here, especially in the dark tones.]

          5. Having applied these settings we now come to the part where we get rid of the haloes that have appeared. They may not be immediately obvious but believe me, they are there. Here's the equalised image to show them...and this was just a small adjustment !!

          6. Select the magic wand tool from the tools palette and left click on the sky. Make sure that the resulting dotted line completely surrounds the aircraft with no bleed through into the aircraft itself. Bleed through occurs where fuselage colour closely resembles the sky colour. If this does happen then you need to use the Polygonal Lassoo tool to draw around the edge where the bleed through is occurring. Bring the polygon shape out into the sky so that you produce a box with sky in it and with one (probably curving) edge running along where the bleed through is occurring. A double left click will set the box. You may have to do this in more than one place.

          7. Use the "Delete" key to delete the sky part layer in this outlined part.

          8. Back to the magic wand tool, left click on the sky again and check that the whole aircraft is outlined. Hit the delete button again. Any haloes that were produced will now be deleted. It is worth noting here that you could leave the background layer active until you have also completed any sharpening, minor brightness/contrast tweaks etc. Deleting the background layer after completing those functions will delete any artefacts in the sky leaving a nice clean sky and will also remove any edge sharpening artefacts such as that thin white outline that often appears around the aircraft.
          Don't forget to select any gaps in undercarriages and flap slots where the sky is visible and delete there as well.

          ...and here's an equalised version after deleting the sky....Bingo ! No more haloes. (No more spots either. They were peeing me off !!)

          9. When you are certain that all of the sky has been deleted go to "Layer"..."Flatten Image". This will merge the layers into one leaving a clean sky with no haloes, no extra grain, no sharpening artefacts and a nicely processed aircraft.

          Here's the finished product with better contrast on the upper roof. Only problem was that I had to select the sky above the roof and nose in two parts and delete using the polygonal lassoo tool due to bleed through into the fuselage when selecting the sky for deletion.


          ...And finally...As I said at the beginning, using the Curves function does the same job as Shadow/Highlight and does not introduce haloes or excess grain unless you go way outside of acceptable adjustment parameters. Getting to know how to use the Curves tool should be a priority for you.
          Last edited by brianw999; 2015-11-07, 14:13.
          If it 'ain't broken........ Don't try to mend it !


          • #6

            LCD monitor view angle calibration.

            Got an LCD monitor ? Are you looking at it at the optimum viewing angle ?
            Here's a useful link to a calibration tool.

            Set the up/down angle of your monitor so that the words Lagom appear faintest or disappear across the middle of screen. The words Lagom should be pale green above the faintest line and pale red below it.


            [EDIT] Link also contains other monitor related issues such as colour balance, contrast etc.
            Last edited by brianw999; 2011-05-30, 14:20.
            If it 'ain't broken........ Don't try to mend it !


            • #7
              6. Here's a link to Paul Nichols' contrast tutorial....

              link removed for maintenance.
              Last edited by brianw999; 2017-12-20, 12:41.
              If it 'ain't broken........ Don't try to mend it !


              • #8

                A lot of images that we screen are uploaded using Adobe RGB as the colour space. This setting does not display well on the web and uploaders should instead use sRGB for the best web based results.
                If you use Photoshop then you can set your colour working space to sRGB and get Photoshop to convert any incoming images that are not using that colour space. If you use other processing software you should also attempt to change to sRGB.
                Here's how to do it....

                You can set sRGB in PS (Your working colour profile) and also ask it to warn you if there is a mismatch with your PS profile. You can then select an option to convert the incoming image to your working profile (sRGB)

                Go to "Edit" .... "Colour settings" in PS. You will see this set of commands.

                Set what I illustrate here (note especially the tick in the "ask when opening" box by "Profile mismatches") and when you open an image it will probably tell you that there is a profile mismatch. Like this..

                Select the option that I have selected.

                You will now be working and saving using sRGB.
                Last edited by brianw999; 2015-11-27, 15:49.
                If it 'ain't broken........ Don't try to mend it !


                • #9
                  9. The Luminosity histogram.

                  I'm not going to reinvent the wheel here because there are others who have written far more detailed explanations than me. This link takes you to an excellent comparison between the RGB Histogram and the Luminosity Histogram.....


                  In Photoshop CS, when you are adjusting the histogram for brightness and contrast (and you will often see a comment in the forum or in a rejection to "check and adjust the luminosity histogram" when you get a Dark/Under and/or Contrast rejection, especially from me) then you should be using the luminosity histogram rather than the default RGB histogram that you see when you go to Image....Adjustments....Levels .


                  The luminosity histogram can be found in "Window....Histogram". Select this option and park it in a corner of the screen. Click the middle tab named Histogram and using the drop down find and select Luminosity.
                  You cannot work directly on this histogram.....

         now you need to go to "Image....Adjustments....Levels" where you can make adjustments. Make sure that you have RGB selected here. You will see three arrows on the baseline of the graph. The left side arrow adjusts the dark tones, the middle arrow adjusts the midtones and the right arrow adjusts the highlights.

                  You might also see that the two graphs are a different shape and may well have different gaps at each end. These gaps indicate missing dark and light tones depending on which end of the graph they are at. You need to drag the relevant arrow in to touch the graph where it meets the baseline. Make the adjustments on the RGB graph but watch the effect on the Luminosity graph. Setting the left and right side of the luminosity histogram will set optimum contrast. You may have to adjust the midtones as well especially if you have deep shadows or bright highlights but this is a personal judgement for you to make.

                  So, remember, when you process use the Luminosity Histogram to set optimum brightness and contrast.
                  If it 'ain't broken........ Don't try to mend it !


                  • #10
                    10. Edge halos, how to get rid of them.

                    I take no credit for this, that goes to Angelo Bufalino for this video showing how to deal with those fine white outlines you sometimes get on high contrast edges.

                    If it 'ain't broken........ Don't try to mend it !


                    • #11
                      This thread is not for general use. Please use if you have any questions. Any questions and answers have been moved to that thread. Thank you.
                      If it 'ain't broken........ Don't try to mend it !