Working with RAW images - the basics

Discussion in 'Graphics Programs and Photo Gallery' started by PJcam, Jan 22, 2018.

  1. PJcam

    PJcam No longer a newbie, moving up!

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    I have downloaded RAWTherapee looks like a great program, now where do I start?

    Can anyone provide any links or videos to get me started?

    I have seen some videos on Youtube mainly altering colour, contrast, exposure, etc, but at this stage just basic working with the files and 'cropping and saving' them would be s good start.

    Thanks in advance.


     
  2. 480sparky

    480sparky Chief Free Electron Relocator Supporting Member

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    Treat every image individually. There's no one-size-fits-all cookie-cutter method. If an image needs sharpening, sharpen it. If it need a bump in contrast, bump the contrast up a bit. If it needs more saturation, move the saturation up some. Or, if your aim was monochrome, desaturate it. Does it need straightened? Cropped?
     
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  3. john.margetts

    john.margetts No longer a newbie, moving up!

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    If the slider will move a long way, don't. Only move it a small amount. It is too easy to get carried away and rack the sliders right over to the right.
     
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  4. KmH

    KmH Helping photographers learn to fish Supporting Member

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    DSLR cameras generally come with a Raw converter app supplied by the camera maker.

    With Raw files first distinguish between global and local edits.
    Global edits are done to the entire image.
    Local edits are only done to part of the image.

    As mentioned each image generally has to be evaluated independently.
    However, if you have a series of Raw images that were all made using the same lighting, and assuming the Raw converter you have has the capability, the global edits applied to 1 image can be 'synced' to all the other images in the series.

    There are 2 global edits, known as 'presence' edits, that I apply to virtually every digital Raw file I make.
    The first is a boost to the mid-tone contrast. The second is a boost to color saturation that is limited to colors that are more subdued that others.

    I use Adobe Camera Raw to edit my Raw files and ACR's basic panel has 3 Presence sliders:
    • Clarity - which adjusts mid-tone contrast.
    • Vibrance - which controls the color saturation of only the subdued colors in the image.
    • Saturation - which I don't often use because it adjust all the colors in a scene.

    Whatever other edits I do from there generally vary from image to image.

    Note too there is a big difference between monochrome and B&W.
    Monochrome is the equal de-saturation all all colors yielding a low overall contrast image, while converting to B&W from color involves adjusting the de-saturation of colors more selectively.
     
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  5. Ysarex

    Ysarex Been spending a lot of time on here!

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    That's a tall order for a forum post. I just got back from my walk to the grocery store. How about I walk you through one with annotations?

    Here's the raw file to download: SAM_8354.SRW

    That's one of my favorite trees there on the right but the reason I took this snap was the new paint job on the duplex. I didn't think my wife had seen that yet and so I grabbed a snap to show her. Here's the processed image directly from Raw Therapee:

    SAM_8354.jpg

    Here's the RT adjustments panel -- I yellow highlighted them (just under the histogram). From left to right you have Exposure, Detail, Color, Wavelet (special effects), Transform, and then not visible Raw and Metadata.

    rt_adjustments.jpg

    Download that raw file and open it in RT. Start with the Color adjustment panel and open the section Color Management (list bottom). You need an input profile. Camera standard should be selected and for this file (Samsung EX2) you'll have to accept that. Note the option for Custom and the drop box. RT ships with a bunch of camera input profiles for some of the more popular cameras and your T6 should be included. For your camera you could select either the Camera standard or the Custom profile or in the future make your own.

    Working Profile should be ProPhoto. If it isn't then change it.
    Output Profile should be............... decision time and pause:
    Raw converters now days fall into two categories. A) Only or mostly a global adjustments capable raw file processor and B) Capable of extensive local adjustments. RT is in category A). That means you're going to run into photos that you'll want to start in RT and then finish in a pixel level editor like PS (recommend Affinity). If you expect to continue working on the image in a second application then the Output Profile should be ProPhoto however if you plan to use RT to deliver the final image then the Output Profiles should be your target output profile. In this case we'll use only RT and so set the Output Profile to RT-sRGB.

    Close Color Management and open White Balance. You need WB values for temp and tint. You can select and option from the Method drop box which may get you close or you can measure something in the photo with the dropper that you know was neutral in color or you can measure a reference that you shot. I shot a reference (piece of white Styrofoam) in a later frame and so I can give you those values: Temp = 5250 and Tint = 1.20. Close White Balance.

    That's all you need for Color Adjustments. I'll start another post to continue.

    Joe
     
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  6. Ysarex

    Ysarex Been spending a lot of time on here!

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    Continuing from post #5.

    Move to the Transform adjustments panel. Open Crop. (Note an inconsistency of sorts in RT -- some adjustments have an on/of switch next to the adjustment name and some don't). Make sure and toggle the Crop switch on. We can finish the crop later but right now we want to go here and get the grid turned on. See the drop box for Guide Type -- select grid.

    I'm going to just give you all the values here. Otherwise it can take a while to figure them out especially if you're not accustomed to doing this.

    Open Lens/Geometry -- open Rotate and set a value of -.9.
    Open Perspective and set a vertical value of 16.
    Open Distortion Correction and set a value of -.177

    Back up in Crop if the Lock Ratio box is check then uncheck it and you can crop the image by pulling the bounding lines around the image.

    Just for fun Open Lens/Geometry again and note the box at the very top: Auto-fill -- toggle it on and off. Leave it on.

    Now over to the Exposure adjustment panel.

    Open the top item Exposure. Note the Auto Levels button. It's already been pushed once for you. If you push it again at any time it'll work like a reset so be careful. RT does a fair job with the Auto Levels function but I prefer to do better. For this photo the Exposure Comp value is too high. It was just a snapshot and so I was pretty lazy and only set the camera EC to +.3. Seems I could have gotten away with a full +1. Anyway RT 1.2 correction is too much. Set the Exposure Comp value to .7.

    How do I know. Combination of experience and also the fact that I looked at the raw file in RawDigger and it's .7 stop under sensor saturation so I'm going with that.

    Look up to the top of the screen and see the two triangles with exclamation points in them -- one grey and one black. Those are toggle switches for the highlight and shadow clipping warnings. We need to toggle those on and yep, someone tell the developers there should be a state change between on and off in the appearance of the switches! First lets worry about black. Down the adjustment list find Black. Pull the slider way to the right and if the toggle is on a whole lot of the photo will show a white mask over the shadows. Our goal is a photo that just reaches black. Rules: There are rules and yes there are exceptions and if you think you have an exception but aren't sure then you don't: follow the rule. A good photo has black in it. Not necessarily much but it gets there. For this photo we want the darkest shadows to reach black. Set a Black value of 800. Subject to change depending on what else we do.

    Highlights. They get a black mask when the toggle is on. This photo has both specular (shiny reflective) and diffuse highlights. The specular highlights should clip and the diffuse highlights should not. The brightest diffuse highlight is the cloud right about the roof line of the nearest building. Adjust the Highlight Compression value until the diffuse highlights don't clip. I set the value to 35.

    On to the next post.

    Joe
     
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  7. Ysarex

    Ysarex Been spending a lot of time on here!

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    Continuing from post #6.

    I stopped the last post with the highlight and shadow clipping because those values are different than these next values. Do those by the numbers not by what you think you like. Black point must be reached and shouldn't be excessive. If you don't have that right you're probably screwing up. The diffuse highlight should be as bright as possible but not clip. I zoom in on the brightest diffuse highlight and get fussy about that value.

    This is an easy photo because the lighting is real easy. No need to get into some of the more advanced stuff like Shadow Compression. This photo almost processes itself. I changed Lightness Contrast and Saturation. I set Lightness to 15, Contrast to 45 (I like contrast) and Saturation to 8.

    Now close Exposure. I'm a believer in a little corner burning or slight vignette -- old darkroom habit. Open the Vignetter Filter and just set small .2 Strength value.

    RT has one local adjustment that it's capable of: It can apply a gradient. This photo could use one.

    gradient.jpg

    At the bottom of the photo you see the gradient tool. Open the Graduated Filter adjustment. In the left upper corner click on the tool icon. Grab it on it's side and flip it over. Position it like you see it above -- pull in the short limits some. Set the Strength value for .3.

    This is a local adjustment. In more difficult lighting a photo might benefit from many more and more extensive local adjustments. This is where RT falls as I mentioned earlier into category A) and can't do that job. Those photo will require you move to a second application. RT does handle this photo well enough.

    Now to Detail. P.S. In the upper left corner of the screen are a collection of tool icons. You'll note that when you close the Graduated Filter adjustment the tool will stay on the screen. Just go up to the tool icons and click that tool. RT likes the "toggle" model for lots of stuff.

    OK, Detail panel. Default Sharpening is usually very good. I like a little micro contrast. Open Microcontrast and check the box for the 3x3 matrix then toggle Microcontrast on.

    If you zoom in to 100% on this file and say look at the wall on the duplex over the doors you'll see some noise. This is my little pocket camera with a 1/1.7 sensor. I love it but it's old and noisy like me. I don't mind the noise but some folks will prefer a little smoothing. Open Noise Reduction and set the Luminance value to between 20 and 30.

    One more post.

    Joe
     
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  8. Ysarex

    Ysarex Been spending a lot of time on here!

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    Continuing from post #7.

    Output time.

    Head over to Transform panel again. Toggle on Resize and open it up. Set the value in the Specify drop box to Width and in the Width box bellow type in the value 1024. Open Post Re-size Sharpening and set the radius to .3 and the amount to 125 (unsharp mask) -- make sure and toggle it on.

    In the lower left corner of the screen is an icon for the disk drive with and arrow on it. Click and that will open your output dialog. Select where you want the output file placed and select File Format JPEG an JPEG quality 100. Click OK and you should have an identical version of the photo I fist posted.

    Keep practicing.

    Joe
     
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  9. PJcam

    PJcam No longer a newbie, moving up!

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    Thanks everyone for your comments, many thanks also Joe for the details you have provided for RT, bet you don't now what I will be doing today. The weather is dull with heavy showers so it is a good time to spend learning more about RT. I am sure this post could help others at some stage also. Lots of detailed help, thank you.
     
  10. PJcam

    PJcam No longer a newbie, moving up!

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    Whilst I work through Joe's lesson on RT, I have one other question, it may come to light as I go through Joe's posts but here it is anyway.

    I have an image of a bird, the bird takes up less than 1/4 height of image, lens couldn't reach far enough. Now say I want to crop the image to just have the bird with a small area of sky or similar around it. I want to crop the image to end u with just the area shown in RT, how do I do that? I managed to prepare and move a cropped area ready, the area outside the box greyed the area to keep as original image with dotted line round it. I don't seem to be able to get past this stage?
     
  11. PJcam

    PJcam No longer a newbie, moving up!

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    I am working through the details provided Joe, but cannot find the following in my drop down list

    Alphabetically the list goes to Samsung CLX-9252 9352 Series then to Samsung K401 Series???

    I am proceeding without setting the above at this stage Joe, then I come to

    Not sure where Back up is?
    But Lock Ratio is ticked
     
    Last edited: Jan 23, 2018
  12. Ysarex

    Ysarex Been spending a lot of time on here!

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    RT doesn't supply a custom input profile for my compact -- not important enough camera. So you have to settle for the Camera standard profile. In some cases even if there is a custom profile you may prefer the Camera standard profile. You have a T6 and that camera is popular enough that there's probably a custom profile available.

    I meant back up as in go back to Crop. Lock ratio will force the Crop tool to adhere to an aspect ratio. This can be useful if you plan to print the image to a fixed size. I never do that and so I prefer to crop an image to fit the image so I check off the Lock ratio option.

    Joe
     
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