reasons and methods of removal
At one time, I often had to deal with problems such as incorrect color rendering, color noise and artifacts that spoil the frame. Therefore, I decided that it would be useful for novice photographers to know the reason for the appearance of spurious shades in photography and how they can be dealt with – during the shooting process and during post-processing.
What are spurious shades
Undesirable or spurious shades are shades that appear in a photograph due to a random color shift. As a result, the picture looks unnatural. Moreover, this can concern both the entire image and its individual sections.
However, sometimes, if I need to stylize an image using toning, I can specifically use the Color Shift effect. But in other cases, incorrect color rendering negatively affects the perception of the photograph. For example, in a winter landscape photo, the snow will look dirty.
Or the model's skin may take on a greenish tint due to reflections from the light passing through the leaves.
Types of spurious shades
First of all, let's figure out what color distortions you may encounter. Let's look at their main varieties.
Noises
In photography, noise is an effect that causes random pixels of different colors or brightness to appear in an image. In analog photography, the problem was most often related to film defects or errors during development.
In digital cameras, the frame is focused on a matrix – a silicon wafer consisting of many semiconductor phototransistors. Through optics, light particles (photons) are converted into electrical potential. In turn, the photosensitive element is supplied with power from the battery. As a result of mixing electrical signals, interference can occur, which causes the appearance of digital noise – random dots (pixels) of different brightness and color.
Color rendering suffers due to chromatic noise. In the image, multiple green and lilac dots appeared in the sky area, and red dots appeared in the area with thickets along the shore. They will become especially noticeable if you view the photo on a large screen or when printing.
Color artifacts
Chromatic artifacts or aberrations occur in an image due to optical distortion. Light passed through the lens is refracted and splits into individual colors of the spectrum. This can lead to the appearance of various distortions – in the photo – multi-colored highlights, stripes along the contour of contrasting objects, rainbow rings.
Artifacts appear especially often when shooting contrasting objects. So, a purple halo is clearly visible around the moon.
Uneven lighting
Color rendition largely depends on the nature of the light. It happened to me that while filming the same scene, during the day and in the evening, I got completely different shades. As dusk deepened, the red colors gradually merged, and the orange and yellow colors almost completely disappeared, so blue predominated in the photo.
The intensity of the light flux also affects color rendering. In a brightly lit room, light shades often disappear, and if there is little light, then in shadow areas, dark surfaces appear gray or black.
Color distortion is best illustrated by the results of underwater photography. At depth, the red shades of the spectrum fade most quickly, therefore, especially if you do not use a flash, the image is dominated by blue, cyan and green tones.
Color shades
Incorrect color rendering can be caused by an effect called surface reflex. For example, you are shooting a person against a green wall. Due to the light reflected from it, the model's face will look unhealthy and pale. And if the model is wearing a bright orange dress, reddish spots may appear on the neck due to reflexes.
The illustration clearly shows that the girl’s face has acquired a jaundiced tint.
Reasons for the appearance of parasitic shades
So, now you know what defects you can encounter in photographs. They can be avoided if you understand the cause of their occurrence.
Wrong white balancing
This problem is often encountered by beginners who rely on automatic settings; I also experienced it in my time. The fact is that the presets built into the camera such as “Sunny day”, “Cloudy”, “Electric light” are configured quite averagely. Therefore they do not always work correctly.
Compare how the pictures differ. In the first version, the white point was taken incorrectly, so the photo turned out to be too cold – the skin tone was unnatural, the greens had a poisonous hue.
Photography errors
Another problem for an inexperienced photographer is incorrect camera settings or an incorrectly chosen technique. Very often, for beginners, photographs become very noisy. This is most often caused by raising the ISO too high in low light conditions. Interference can also appear due to too long a shutter speed – due to the increased amount of light falling on the matrix.
The photo was taken in the evening in cloudy weather. To prevent the photo from being too dark, the ISO was raised. As a result, noise is visible even without magnification. And if you zoom in, red and blue pixels become clearly visible, especially in the sky.
Lighting Features
Another common mistake is not taking into account the nature of the light. I encountered her when I first went out to shoot outdoors. Trying to catch beautiful highlights, I photographed the model through the foliage of trees, not taking into account the reflected light. As a result, I got green spots on my face.
It also happens that beginners use a background that is too bright without taking into account the angle of incidence of the light – in this case, unwanted reflexes also arise.
Traditional photo in sunflowers. The glare from the leaves gave the girl's skin a greenish tint, which was further intensified by the green makeup.
Lack of equipment
The cause of noisy photography may be a poor-quality matrix. Although manufacturers of low-budget cameras (this applies to both photographic equipment and smartphones) indicate high resolution in the characteristics, the silicon photosensitive element in such equipment is smaller in size than in expensive models. As a result, the distance between the pixels on the matrix is smaller, and during operation it quickly heats up. This leads to an increase in the electrical signal and, as a consequence, an increase in noise.
Chromatic aberrations often occur due to the use of poor quality optics. In advanced models, lenses are made of low-dispersion glass. In addition, the optical system uses aspherical elements. Such lenses compensate for geometric and chromatic distortions even at the shooting stage.
The photo shows a halo surrounding the bright pink petals and dark green leaves. As a result, the flowers look unnatural.
Errors in post-processing
In an effort to correct shortcomings made during shooting, it is important not to overdo it. For example, trying to increase the detail of shadow areas can result in even more noise. Another common mistake that occurs when trying to get rid of surface reflections and correct color correction is unnatural shades.
Or, if you don't take temperature into account when correcting white balance, you may end up with overly warm or overly cool colors. And when adjusting the exposure, the photo comes out overexposed or gaps appear in the shadows.
Problem areas can be seen if you open the image in a RAW camera (screenshot on the right). The loss of detail in the shadows is highlighted in blue, and the highlights in red. Due to attempts to remove the bluish tint caused by the evening lighting, the girl’s skin became unnaturally pale.
How to avoid unwanted shades
Of course, most mistakes made during shooting can be corrected in post-processing. But why add more work to yourself if many shortcomings are easy to avoid.
White balance correction
Don't trust automatic settings. And you shouldn’t completely rely on the reliability of your vision, especially if you haven’t yet been able to see enough and haven’t developed an intuitive sensitivity to colors. For example, although I consider myself quite experienced, I always keep a white-gray card in my photo bag.
It is better to make adjustments more efficiently on the gray side – the white side can change color due to tint reflections:
Point the lens at the card. It needs to cover more than half the frame, and the focus should be in the center of the “target”. Make sure the light hits the card at the same angle and intensity as the background behind it.
Turn on auto white balance, set the shooting mode to Program (“P”) and take a photo.
Remove the card. Set the camera to manual mode. Select a photo from which the camera considers a color rendering standard – a photo of a gray card. Next, go to “Custom” mode.
Don't forget to reset the balance after you finish shooting. And, if the lighting conditions change during the process (the sky becomes cloudy, it gets dark), you will need to reconfigure.
Calibrating Equipment and Lenses
The camera sensor and the human eye see the world differently. To avoid color rendering errors, you should first calibrate the camera. To do this, you will need a color target – a table of color standards.
I recommend using X-Rite ColorChecker Classic-24. It contains 18 basic tones and 6 grayscale slots. The surface of the table is matte, which eliminates the appearance of unwanted glare.
A photo of the target is taken with standard lighting parameters. Please note that if conditions change, a different standard will be required. After this, profiles for the camera are created using special programs (Adobe DNG Profile Editor, Argyll CMS, etc.).
Optics usually do not require calibration. Unless there are critical problems with the image, regular cleaning and periodic preventive maintenance may be sufficient. But if you notice constant color rendering defects and strong aberrations, then most likely the lens needs adjustment. This process is quite complicated and involves adjusting optical parameters, so it is better to entrust it to the service center specialists.
Use quality equipment and avoid cheap lenses
As noted above, many errors are associated with imperfect equipment. If you want to take great pictures, don’t skimp, especially when it comes to the lens. However, if you have a budget cropped camera, this is not so scary. Just be aware of the risks of overheating the matrix. Take breaks from shooting when shooting in Sports mode. Well, in principle, noise suppression is not the most difficult process.
But it is not always possible to correct color distortions caused by imperfect optics. Therefore, choose fast lenses with good optical systems.
Removing spurious shades from photographs
If you couldn't avoid problems while shooting, post-editing will help. I'll tell you how to correct the most common color rendering errors.
First, let's learn how to correct white balance. We will improve the winter landscape. Due to incorrect settings, the snow came out a bit dirty.
Let's upload the photo into Adobe Photoshop. Ideally, work with RAW files, but if you have a photo in JPG, then after importing, immediately go to the “RAW Camera” filter to correct mistakes made during shooting.
Go to the “Basic” section. To select the setting point, take a pipette.
We select the whitest possible area as a reference. Try sampling in different areas to achieve the desired tone.
Now that the temperature is lowered, you can adjust other parameters – adjust the amount of light and shadows, adjust clarity, etc.
Accept the changes by clicking “Ok”.
Let's look at the result. Now the snow is really white and clean, but we have retained the slight pink haze of a winter morning.
The next thing I want to talk about is how to deal with noise. This is a typical problem when shooting in the evening with an excessively high ISO. Here in the example picture the sky is very noisy.
Uploading a photo. Of course, you can go the simple route – use the “Noise” filter. But in this case, you can lose sharpness – the already blurred background may simply get lost.
Go to “RAW Camera”. Select the “Detailing” tab.
Expand the sections “Noise Reduction” and “Color Noise Reduction.” Move the sliders to remove unnecessary pixels.
To avoid loss of clarity, go to the “Adjusting Sharpness” section. Increase the value of the Masking and Radius parameters.
We accept the changes and, after returning to the editor window, save the file.
As you can see, getting rid of multi-colored dots in an image is not so difficult.
Now let's learn how to get rid of shortcomings caused by lighting features.
The photograph was taken under electric light. Because of this, the picture is excessively yellow. Let's fix this in a few steps:
Open the file. Create a duplicate layer.
In the “Image” tab, go to the “Correction” – “Replace Color” section.
Using a pipette, select the shade that requires correction.
Check the box to select whether you want to perform the replacement on the entire image or just a specific area. Move the sliders to change the shade.
The next step is optional. But you can go to the “RAW Camera” to more accurately equalize the temperature and hue.
Now we return to the main editor. We combine the layers and save the file.
Feel the difference – the picture is no longer yellow, the colors have become natural.
And one more way to get rid of reflections and color rendering errors. I’ll show you how to remove spurious shades not from the entire image, but selectively.
For example, I took a photo with a popular subject – a girl in a field with sunflowers. There are two problems that need to be solved in this photo – the red-haired girl’s hair has gone magenta due to color rendering errors, and her skin looks deathly pale due to background reflections.
Open the photo in the editor. Create a duplicate layer (if an error is made during the editing process, this will allow you to quickly return to the source).
In the Adjustments section, select the Photo Filter option.
Click on the highlighted icon so that the adjustment layer is linked only to the duplicate background, without affecting the main image.
Choose a filter color that is as close as possible to your skin tone. Here you will have to act empirically. I chose Deep Emerald.
Select a brush. Adjusting the size and transparency.
Select black stroke color. Now carefully wipe off the unwanted greenery from your face.
Having restored the natural skin tone, we create a new layer of correction. Now in the filters we select Magenta to remove purple shades.
We repeat the previous steps – take a black brush and erase the purple from the hair so that it looks natural red.
Now we combine the adjustment layers with the duplicate of the original one to see the result. To do this, select the image thumbnails – hold down “Shift” and click with the cursor. After that, go to the “Layers” tab or simply call the context menu with a right click.
The result satisfied me, I can perform mixing. And all that remains is to save the file.
Compare the result with the original – progress is obvious. The skin is of normal color, the hair is a beautiful copper color.
Good analogues
I myself prefer to use Photoshop. But if this program is no longer installed on your PC, then there may be a problem with the installation. Now in Russia it is impossible to officially purchase licensed software, and downloading hacked versions from torrents carries certain risks. It is not a fact that the software will work and will not download a bunch of Trojans onto your PC.
But don't be upset. No matter how good Photoshop is, it must be admitted that for beginners this program may seem too complicated. If you are not a professional photographer or retoucher, most of the features offered by the editor will remain unclaimed. Therefore, I consider it necessary to introduce you to available analogues. I tested all the programs personally and was pleased with the results.
Affinity Photo – for those who prefer licensed software. True, purchase is possible only through an official representative office in Belarus, but there will be no problems. In terms of functionality, it is not much inferior to the reference editor from Adobe. A big plus is that there are presets for retouching in frequency decomposition. Of the minuses, it is worth noting the lack of Russian localization.
PhotoMASTER – an ideal solution for beginners. An editor from a domestic developer with an intuitive interface. Editing can be done automatically or manually using levels and curves. There are many pre-installed filters and AI retouching tools. Supports all popular graphic formats and is equipped with a RAW converter.
Pixlr – for solving one-time problems. The online editor allows you to correct photos without installing software on your PC. The interface resembles Photoshop, so you can use my instructions. In addition to photo processing, on the platform you can create design projects for social networks and websites using the built-in collection of templates.
Let's sum it up
If you plan to engage in photography professionally, you need to take into account that only images of impeccable quality have commercial value. Effluents place particularly high demands. For a photograph to sell, it must be free of noise and chromatic artifacts, and the colors must look natural. And private customers have high demands on the result – believe my experience.
Well, in any case, a picture without spurious shades, unless the picture is specially tinted to achieve an artistic effect, looks better. Avoiding mistakes when shooting or correcting them in a photo editor is not so difficult. And the result will be cool photos that will delight both you and your friends and subscribers, I guarantee you that.
