PHOTOGRAPHY POST PRODUCTION
Part 1
Introduction
Post processing is an integral part of digital photography. It's not used to manipulate the image but to correct it to match the real scene. Our camera sensors are not perfect .. actually far from perfect. It can never capture what you can see with your eyes. In good old analog days, most of the good photographers had their own processing dark rooms where they would painstakingly process the images. It required lot of technical knowledge including chemistry. Thus this was limited to only few people and it was quite secretive knowledge. In digital era, with Digital Cameras and Post-processing software almost anyone can start immediately. The term "post-production" seems new or something of taboo to many thinking it is kind of cheating and hence we should only rely on what's come out of camera as authentic image. Problem is our camera sensors cannot capture what you see hence all camera does the post-processing "in-camera" so that it may closely match with real scene. So what ever you see coming out of camera is already post processed. This is actually true, if your camera output is JPEG file format. Problem is you camera does not know what you are capturing and what that should exactly look like. Thus, in-camera post production never give excellent or amazing outputs.
File Format
When you are shooting images in JPEG file format, your camera is already doing the post processing in-Camera. Most of the time this will not give you correct result since end-of-the-day the camera uses some set of algorithms based on your settings to process final image. And .. it's not a human. Most DSLR has setting to set default contrast, brightness, vibrance, clarity. Point-and-shoot or semi-professional DSLRs have settings such as "Portrait", "Night Time", "Scenery" modes. Based on these settings the camera would apply appropriate "post-production" pre-set values before giving out final output. The LCD preview that we see on a DSLR is actually a JPEG version of the image after applying "post production" settings no matter which format (JPEG/RAW) you shoot in.
The only way you can have images that makes people "wooow" is to post-process it by yourself. So, you need to use an image format that does not have any processing but has all the camera settings parameters intact when the picture was snapped. RAW image format is one such format. Each camera vendor has their own RAW image format but they all serve the same purpose.
Getting it Right
Just remember, it is really really hard to post-process a bad picture into a good picture. On the contrary, it is really easy to make a good picture into a "wooow" picture using correct post-processing. So getting it right "in-camera" is critical to have beautiful images.
It is possible to apply post-processing to any Image format including JPEG. Problem is, the chroma and luminance values are already fixed based on a defined color dynamic range in such formats. If you change anything, the whole image would degrade in quality.
Software to use
Adobe "Lightroom" is industry de'facto for post processing. I have used Apple "Aperture" for quite sometime and have recently moved to "Lightroom". "CaptureOne Pro" is also used by many fashion photographers. Both Nikon and Canon provides their own software that allows some level of post-processing. These software allow you complete work-flow from importing images from camera to cataloging to touch-up to final output. Photoshop could also be used to achieve the post-processing it cannot catalog and manage images. However, Photoshop allows you to further enhance your capabilities in advanced photography that involves focus stacking, Image stitching, exposure blending, composites etc. although there are other software that could do these tasks but if you are using Lightroom, it is better to use photoshop since the work-flow is integrated.
POST PRODUCTION PARAMETERS
There some key areas that you could change in Post-production. I will lay them out in sequence of importance.
A. White Balance
You HAVE to HAVE your white balance correct. This is the first thing you do. This is very very important if you are shooting in JPEG file format by relying on "in-camera" post-production. In RAW format even if image does not look ok on camera LCD, you can change the white-balance in post-production without degrading the image quality. But you must be able to do this properly. I used something called ExpoDisk. It is a disk that you put in front of your camera lens and camera would use that to set "Custom" white balance values. Excellent tool if you are shooting JPEG format. I still use this even though now I use RAW format. This helps me to see the correct white-balaced image on the DSLR LCD panel. Remember, whatever you see there is "in-camera" post processed JPEG version. There are other easy way to achieve same result without spending any money and I will discuss this shortly at the end of this section.
In digital imaging all colors are calculated in relation to what natural gray color looks like. The problem is on different light conditions it is not possible for a camera to identify which one is gray color. Thus most of the time Camera always makes mistake. This is why setting the White Balance to "Auto" sometime yields interesting results. Same subject looks different under sunlight, Fluorescent light or under shades. In RAW format this is not an issue since colors values are not hard coded in the image and you can change or shift that based on your choice outside of the camera. However, if you are looking at the LCD of your camera or using JPEG Format, choosing the correct white balance is critical. I always set the white balance to "daylight" mode. In this mode, camera does not add any color cast to fix anything. With RAW format shooting, you can always change white balance in post production without degrading image quality.
In digital imaging all colors are calculated in relation to what natural gray color looks like. The problem is on different light conditions it is not possible for a camera to identify which one is gray color. Thus most of the time Camera always makes mistake. This is why setting the White Balance to "Auto" sometime yields interesting results. Same subject looks different under sunlight, Fluorescent light or under shades. In RAW format this is not an issue since colors values are not hard coded in the image and you can change or shift that based on your choice outside of the camera. However, if you are looking at the LCD of your camera or using JPEG Format, choosing the correct white balance is critical. I always set the white balance to "daylight" mode. In this mode, camera does not add any color cast to fix anything. With RAW format shooting, you can always change white balance in post production without degrading image quality.
i. Color Temperature
The main settings of a White Balance is the color Temperature or light temperature in Kelvin scale. When something is warm or hot it radiates Red or Orange or yellow light based on the heat in generates. When something is cold it looks blue. Usually 5000 K heat is thought to be produced by natural light. The White balance settings found in DSLR are usually put in the order of their temperature. With "Tungsten" being warmest to "shade" being coolest. So there will be a color cast on your image based on the kind of light source being used.
White balance color temperatures on the Camera are exactly backwards from the Kelvin scale. White balance color temperatures are backwards because the white balance system adds color to make up for a lack of a particular color in the light that is shining on your subject.
For instance, under fluorescent light, there is not enough blue light, which makes your subject appear greenish yellow. When blue is added, the image is balanced to a more normal appearance. White balance in cameras adds colors to balance the camera for the current light source. So, if you choose "fluorescent" white balance, you camera would add a blue color cast to make the image look neutral.
Another example is when you shoot on a cloudy, overcast day. The cool ambient light could cause the image to look bluish if left unadjusted. The auto white balance control or "Cloudy" setting in your camera sees the cool color temperature and adds some red or warm colors. A normal camera white balance on an overcast day might be about 6000 K (Kelvin), which will warm up the cool bluish look. Note that camera has some pre-set values for this. It does not analyse the image and add variable color cast. It is fixed. However, real-world is different. You environment may not be of exact color temperature that camera pre-sets are designed to use. So, manual fix becomes important.
Just remember, we use the real Kelvin temperature range in reverse, and in photography reddish colors are warm and bluish colors are cool. Even though this is backwards from what we were taught in school, it fits our situation better. So, if you choose "Shades" which is cooler color , Camera would add a warm color tone to your image to reduce the blue tone. Following is table showing the color cast that Camera will add for each White Balance pre-set settings. You could easily notice that it is in reverse scale. So where "Shade" means you have Cooler temperature, the camera actually adds color for higher temperature. This is something we could use creatively as well. But I will leave that discussion for some other day.
Problem with this is that these Pre-set white balance settings are mapped for specific color value for a specific heat. for example, if you choose "Cloudy" camera would try to add a color cast for 9000 K to 10,000 k. That's lot of red-yellowish tone. But most of the time you scenery will not match the exact temperature map the camera has in pre-set settings. So, you will get extra color cast or tone in your image which is not indented. At post processing you could choose any temperature to add the color cast making the image look neutral and natural.
ii. Tint
"Color temperature" settings helps you to counteract the color cast from natural light sources producing either bluish (cool) or red-ish (hot) color cast. However, man made lights create color cast of green or magenta. Fluorescent and other artificial lighting may require significant green-magenta adjustments. The "Tint" settings under White-Balance is used in post-production to shift the color tone to increase or decrease the green or magenta tones.
Check the sample image below. The camera was set to Auto White balance in the first image. You could notice that it has excess yellowish/red color cast. The image looks really warm like mid-day sun light. However, it was shot around 10 am in the morning. The camera calculated the Temperature to be 5050 K. In the second image, I have manually reduced the temperature to 3350 K in Lightroom and the picture now looks neutral with natural white light.
Easy way to do this
If you think it is quite hard to manually change the color temperature since you are not sure what should be the correct color, then there is easy way out other than using something like ExpoDisc that I use. If you have something in your image that you know as pure white then you are in luck. Lightroom or similar applications allows you to select a color in the image that you think as white. Once you do that, Lightroom would calculate correct temperature and apply changes accordingly. I would advise to snap one image having your model holding a white piece of paper. If there are no model involved, just place the white paper in frame and take a picture before starting actual shooting. If you are shooting in JPEG format then try to take few pictures using different "White Balance" settings with the White Paper in the frame. Choose a White Balance that closely matches white color on LCD.
Let us assume that there is a white color in your image and it really does not look white due to incorrect color cast. Best way to identify what is white in your image is to sample a color that you think is white. Use the color picker tool in your image editing or Post-processing software to find this. Remember, white color has same amount of red, green and blue in it. So if a colored items has same amount of Red Green and Blue value, then, that is your white color even though it might look different. This process works best with RAW file formats but it is applicable for JPEG as well. Example: Let us assume that you have photographed a white rose. However due to color temperature and tint issue it looks greenish. You can use the White balance color picker to select parts of flower that you think is white. Lightroom will change all the colored pixel having that greenish color to white. Then it will shift colors of all the other pixels in the image with respect to that color shift. This works quite well until you have something in the image that is actually green (example, leafs) ! Then that green colored item will also be changed to white or closer to white depending on how closely it matched with selected color ! yes. that is the problem with JPEG image and RAW does not really suffer from this.
Lightroom really makes it simple. There is a tool panel for white balance settings where you can slide Color temperature and Tint value easily and see the changes immediately in the image.
Notice the Color dropper tool. If you click on it the dropper will float on your picture and you can select a point that you think is white in the image.
Good news is that the dropped icon also shows the color values of the pixel that you are pointing to as well as surrounding pixels in zoom view. Notice the percentage that it shows below. You should be looking for a color where all these values are quite close.
This is how I have fixed the sample image above. I know that the Model's eye should be white. So I used that as a reference. I hovered the Neutral Color Picker from white balance tool over the eye's white part. I selected a color that had percentage of Red, Green and Blue closely equal. The initial selection gave Color temperature of 3030 K. But looking at that I understood that there little bit of extra blue in the image and the yellow dress really did not look quite the yellow that I witnessed originally. So using that as a reference I slided the Temperature towards right to decrease blue or cooler tone. I found the at 3600 K it looks quite neutral.
Although I have explained the process in Lightroom, but it is exactly same in Aperture and CaptureOne. I have used both. So all Post Processing Application will have something similar which would allow you to do exactly what I did.
What if I shoot in JPEG Only, I have no choice
I also used to shoot in JPEG. There is nothing wrong in it. I still choose JPEG using my iPhone. Check my iPhone photography album on Flickr to understand what can be achieved. It is always better that you do not apply any extra processing "in-camera". So, if you are on Point-and-shoot or DSLR, trying find the preset for image processing. Remember, if you choose "Portrait" mode, the Camera usually selects lower sharpness/clarity and some camera increases the vibrancy. With "Scenery" mode the vibrancy will be quite high with higher contrast as well. It is better to have the all set to zero if possible. Then You have to do White balance properly.
1. Put a white piece of paper or something that is white in the scene that you are going to photograph
2. try selecting the a "white balance" setting in your camera that you think is right.
3. Take a picture
4. Check the result on LCD. If you think the white object is not white enough. Change the "White balance" to something else.
5. Take another picture and verify on LCD. Repeat this until the white object looks close to white. You may not get perfect white but close enough is good enough.
6. Continue with your shooting this settings. Unless the light condition changes you do not need to change anything.
7. Load the images on your Post processing software (Lightroom)
8. Bring the image with white page or card that had White in close or good enough situation.
9. Use the white balance color picker and click on the whitest part of the object. Try selecting an area where the amount of Red Green and Blue color values are almost of same value.
10. Check the result on screen. Change the Color temperature slider to fine tune.
11. Now sync this values with all the other image that you took under the same light condition. Lightroom has a Sync button that copies such settings to all other images or selected images.
Done ! First critical step is complete.
| Color Temperature | Light Source |
| 1000-2000 K | Candlelight |
| 2500-3500 K | Tungsten Bulb (household variety) |
| 3000-4000 K | Sunrise/Sunset (clear sky) |
| 4000-5000 K | Fluorescent Lamps |
| 5000-5500 K | Electronic Flash |
| 5000-6500 K | Daylight with Clear Sky (sun overhead) |
| 6500-8000 K | Moderately Overcast Sky |
| 9000-10000 K | Shade or Heavily Overcast Sky |
Problem with this is that these Pre-set white balance settings are mapped for specific color value for a specific heat. for example, if you choose "Cloudy" camera would try to add a color cast for 9000 K to 10,000 k. That's lot of red-yellowish tone. But most of the time you scenery will not match the exact temperature map the camera has in pre-set settings. So, you will get extra color cast or tone in your image which is not indented. At post processing you could choose any temperature to add the color cast making the image look neutral and natural.
ii. Tint
"Color temperature" settings helps you to counteract the color cast from natural light sources producing either bluish (cool) or red-ish (hot) color cast. However, man made lights create color cast of green or magenta. Fluorescent and other artificial lighting may require significant green-magenta adjustments. The "Tint" settings under White-Balance is used in post-production to shift the color tone to increase or decrease the green or magenta tones.
Check the sample image below. The camera was set to Auto White balance in the first image. You could notice that it has excess yellowish/red color cast. The image looks really warm like mid-day sun light. However, it was shot around 10 am in the morning. The camera calculated the Temperature to be 5050 K. In the second image, I have manually reduced the temperature to 3350 K in Lightroom and the picture now looks neutral with natural white light.
Easy way to do this
If you think it is quite hard to manually change the color temperature since you are not sure what should be the correct color, then there is easy way out other than using something like ExpoDisc that I use. If you have something in your image that you know as pure white then you are in luck. Lightroom or similar applications allows you to select a color in the image that you think as white. Once you do that, Lightroom would calculate correct temperature and apply changes accordingly. I would advise to snap one image having your model holding a white piece of paper. If there are no model involved, just place the white paper in frame and take a picture before starting actual shooting. If you are shooting in JPEG format then try to take few pictures using different "White Balance" settings with the White Paper in the frame. Choose a White Balance that closely matches white color on LCD.
Let us assume that there is a white color in your image and it really does not look white due to incorrect color cast. Best way to identify what is white in your image is to sample a color that you think is white. Use the color picker tool in your image editing or Post-processing software to find this. Remember, white color has same amount of red, green and blue in it. So if a colored items has same amount of Red Green and Blue value, then, that is your white color even though it might look different. This process works best with RAW file formats but it is applicable for JPEG as well. Example: Let us assume that you have photographed a white rose. However due to color temperature and tint issue it looks greenish. You can use the White balance color picker to select parts of flower that you think is white. Lightroom will change all the colored pixel having that greenish color to white. Then it will shift colors of all the other pixels in the image with respect to that color shift. This works quite well until you have something in the image that is actually green (example, leafs) ! Then that green colored item will also be changed to white or closer to white depending on how closely it matched with selected color ! yes. that is the problem with JPEG image and RAW does not really suffer from this.
Lightroom really makes it simple. There is a tool panel for white balance settings where you can slide Color temperature and Tint value easily and see the changes immediately in the image.
Notice the Color dropper tool. If you click on it the dropper will float on your picture and you can select a point that you think is white in the image.Good news is that the dropped icon also shows the color values of the pixel that you are pointing to as well as surrounding pixels in zoom view. Notice the percentage that it shows below. You should be looking for a color where all these values are quite close.
This is how I have fixed the sample image above. I know that the Model's eye should be white. So I used that as a reference. I hovered the Neutral Color Picker from white balance tool over the eye's white part. I selected a color that had percentage of Red, Green and Blue closely equal. The initial selection gave Color temperature of 3030 K. But looking at that I understood that there little bit of extra blue in the image and the yellow dress really did not look quite the yellow that I witnessed originally. So using that as a reference I slided the Temperature towards right to decrease blue or cooler tone. I found the at 3600 K it looks quite neutral.Although I have explained the process in Lightroom, but it is exactly same in Aperture and CaptureOne. I have used both. So all Post Processing Application will have something similar which would allow you to do exactly what I did.
What if I shoot in JPEG Only, I have no choice
I also used to shoot in JPEG. There is nothing wrong in it. I still choose JPEG using my iPhone. Check my iPhone photography album on Flickr to understand what can be achieved. It is always better that you do not apply any extra processing "in-camera". So, if you are on Point-and-shoot or DSLR, trying find the preset for image processing. Remember, if you choose "Portrait" mode, the Camera usually selects lower sharpness/clarity and some camera increases the vibrancy. With "Scenery" mode the vibrancy will be quite high with higher contrast as well. It is better to have the all set to zero if possible. Then You have to do White balance properly.
1. Put a white piece of paper or something that is white in the scene that you are going to photograph
2. try selecting the a "white balance" setting in your camera that you think is right.
3. Take a picture
4. Check the result on LCD. If you think the white object is not white enough. Change the "White balance" to something else.
5. Take another picture and verify on LCD. Repeat this until the white object looks close to white. You may not get perfect white but close enough is good enough.
6. Continue with your shooting this settings. Unless the light condition changes you do not need to change anything.
7. Load the images on your Post processing software (Lightroom)
8. Bring the image with white page or card that had White in close or good enough situation.
9. Use the white balance color picker and click on the whitest part of the object. Try selecting an area where the amount of Red Green and Blue color values are almost of same value.
10. Check the result on screen. Change the Color temperature slider to fine tune.
11. Now sync this values with all the other image that you took under the same light condition. Lightroom has a Sync button that copies such settings to all other images or selected images.
Done ! First critical step is complete.
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1 comment:
Very useful post, hope you will continue.
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