Channels in Photoshop: what they are, what you can do with them | Articles | Photo, video, optics

Do you want to beau­ti­ful­ly increase the con­trast of a col­or pho­to or quick­ly cre­ate a mask, sav­ing as much time as pos­si­ble and avoid­ing man­u­al paint­ing with a brush? Do you need to cut out a sol­id back­ground or a per­son, while main­tain­ing a neat out­line of the hair? Or maybe you are tired of pre­sets and fil­ters and want to tone the pho­to your­self?

In any of these dif­fer­ent and some­times dif­fi­cult sit­u­a­tions, the same thing will help — work­ing with chan­nels. Yes, those very incom­pre­hen­si­ble ones that cause hor­ror among begin­ners. We tell and show visu­al­ly what trichro­mat­ic chan­nels are, and also share tricks on how to cut out the back­ground using chan­nels, tint, increase con­trast and quick­ly get black and white pho­tos.

The sum of the chan­nels of three col­ors gives a full-fledged col­or image with all shades / Illus­tra­tion: Eliza­ve­ta Lentchevicha, Photosklad.Expert / Source: unsplash.com

What are channels in Photoshop

Our vision con­sists of 4 sen­si­tive cones, three of which are respon­si­ble for the per­cep­tion of the three pri­ma­ry col­ors — green, red and blue. When look­ing at an object, such as an orange, the red cones will react more strong­ly, while the green and blue cones will react less. It is their joint work that helps us to see and per­ceive the whole vari­ety of col­ors.

Chan­nels in Pho­to­shop are essen­tial­ly three layers—red, green, and blue—that add up to the col­or image as we see it. It turns out that in each col­or there is a cer­tain amount of each of the three col­ors.

If you take green, blue and red dice and go to the palette Chan­nelsthen the fol­low­ing is seen:

This is the sum of all three chan­nels that togeth­er give a col­or pic­ture / Illus­tra­tion: Eliza­ve­ta Lentchevicha, Photosklad.Expert

• Red chan­nel. With the help of white and black, it shows where there is a lot of red, and where there is not enough. If you click on it, the red plate will be white, and the green and blue ones will be black.

By anal­o­gy, it turns out that in the red chan­nel a white plate is red, there is a lot of max­i­mum red, and the blue and green plates are paint­ed black — there is no red there / Illus­tra­tion: Eliza­ve­ta Chechevit­sa, Photosklad.Expert

• Blue chan­nel. Works the same as red. Where there is a lot of blue, the black-and-white image will be white or light, and where there is lit­tle, black or dark gray.

In the blue chan­nel, blue par­rots are light, and red par­rots are dark, almost black / Illus­tra­tion: Eliza­ve­ta Lentchevicha, Photosklad.Expert

• Green chan­nel. The same as with blue and red. Light areas are where green is present, dark areas where there is lit­tle or no green.

All three col­ors add up to white. That is, if you see a white sky in the pho­to, it means that there is blue, red, and green in the max­i­mum pos­si­ble amount. By con­tra­dic­tion, black is the absence of all three col­ors.

Where are channels in Photoshop?

To find chan­nels in Pho­to­shop, in the com­mand line at the top, find the menu Win­dow / Win­dow — Chan­nels / Chan­nels. After that, a spe­cial palette for work­ing with chan­nels will open.

Open the palette with chan­nels before learn­ing how to process below / Illus­tra­tion: Eliza­ve­ta Chechevit­sa, Photostore.Expert

Why channels are needed — 4 processing steps

Chan­nels can be affect­ed sep­a­rate­ly by chang­ing col­or and con­trast. But, what is even more use­ful, the desired chan­nel can be “iso­lat­ed” in order to make a mask based on it, cut out an object or get a black and white pho­to in a cou­ple of sec­onds. We tell you how to do it.

Color grading with channels

By influ­enc­ing the amount of a cer­tain col­or in the chan­nels, you can cre­ate many high-qual­i­ty ton­ings in a cou­ple of mouse move­ments.

Impor­tant: col­ors change best and most notice­able in bright pho­tographs with a wide vari­ety of shades. For exam­ple, if you are pho­tograph­ing with col­ored light or just bright objects. It will not work well to make a col­or cor­rec­tion of a win­ter land­scape with a min­i­mum of col­ors — it will come out dirty and ugly.

1. Open the palette Lay­ers (you can quick­ly do this with the 7 key) and click on the black and white cir­cle.

2. In the list of adjust­ment lay­ers that appears, select Chan­nel Mix­er.

Chan­nel mix­ing changes the col­or ratio in the chan­nels / Illus­tra­tion: Eliza­ve­ta Chechevit­sa, Fotosklad.Expert

3. Click on the drop down list Out­put Chan­nel. You will see three col­ors — red, green, blue. Select the col­or you want to change. For exam­ple, if you want to affect red, then choose red. Use the Red, Green, and Blue slid­ers to change the amount of col­or in the chan­nel.

So, if you remove the red col­or from the red chan­nel, then it will turn bluish or bluish / Illus­tra­tion: Eliza­ve­ta Lentchevicha, Photosklad.Expert

Thus, by switch­ing between chan­nels and mov­ing the slid­ers, you will get a unique tint.

Impor­tant: below is the total num­ber of col­ors in the chan­nel. It is rep­re­sent­ed by the inscrip­tion Total / Total: +70% (for exam­ple, as in the screen­shot above). For the cor­rec­tion to be of high qual­i­ty, do not allow the sum of the chan­nels to exceed 150–190% (depend­ing on the spe­cif­ic pho­to).

Take a black and white photo in 30 seconds

Open palette Chan­nels and switch between them. Choose the chan­nel with the black and white image that you like the most. Remem­ber your choice.

The most pleas­ing result in this pic­ture is giv­en by the Green Chan­nel / Illus­tra­tion: Eliza­ve­ta Lentchevicha, Fotosklad.Expert

2. On the palette Lay­ers click on the black and white cir­cle and select Chan­nel Mix­er.

3. Click the check­mark Mono­chrome / Mono­chrome. The pic­ture will turn black and white.

4. To get exact­ly the image that you liked in step 1, in the slid­ers with chan­nels, put 100% in the chan­nel that you liked, and 0 in the remain­ing two. Ready!

You can edit the result­ing b/w pho­to by decreas­ing and increas­ing the slid­ers. The main thing is to try not to exceed 150–190% of the total result / Illus­tra­tion: Eliza­ve­ta Chechevit­sa, Photosklad.Expert

How to remove background using channels

With the help of chan­nels, you can cut out the back­ground, even if the object is quite com­plex. For exam­ple, a tree with a lush crown or a per­son with fluffy hair. Also, the chan­nels eas­i­ly cut out a sol­id back­ground. For exam­ple, if you took pic­tures with chro­ma key.

1. Cre­ate a dupli­cate of the orig­i­nal lay­er using the hot keys Ctrl + J.

2. Open the palette Chan­nels and click suc­ces­sive­ly all three chan­nels. You want the one where the back­ground and sub­ject are the most dif­fer­ent from each oth­er.

In this pho­to, the con­trast between the back­ground and the berry in the red chan­nel is the strongest / Illus­tra­tion: Eliza­ve­ta Lentchevicha, Photostore.Expert / Pho­to: unsplash.com

3. Hold­ing down the left mouse but­ton, select the chan­nel with the high­est object/background con­trast and move it to the plus sign in the Chan­nels menu.

You will have a copy of the chan­nel. Click on it with the left mouse but­ton / Illus­tra­tion: Eliza­ve­ta Lentchevicha, Photostore.Expert

4. Go to Image / Image — Cor­rec­tions / Adjust­ments — Lev­els / Lev­els.

In the win­dow that opens, move the black and white slid­ers to the cen­ter to fur­ther increase the con­trast between the back­ground and the object / Illus­tra­tion: Eliza­ve­ta Chechevit­sa, Fotosklad.Expert

5. Click on the dot­ted cir­cle in the Chan­nels pan­el.

March­ing ants will “run” on the image — your chan­nel will stand out / Illus­tra­tion: Eliza­ve­ta Chechevit­sa, Photosklad.Expert

After that, switch to the palette lay­ers, select the copy of the lay­er and click on the black rec­tan­gle with the white cir­cle — the mask cre­at­ed based on the chan­nel will be applied to your copy of the lay­er.

To bet­ter see the result, turn off the vis­i­bil­i­ty of the Back­ground lay­er. To do this, click on the icon in the shape of an eye / Illus­tra­tion: Eliza­ve­ta Lentchevicha, Photosklad.Expert

Impor­tant: If the object is miss­ing instead of the back­ground, click on the mask and invert it. To do this, press Ctrl + I.

6. If the mask turned out to be imper­fect, it needs to be final­ized! Open palette Prop­er­tiesclick on the pic­ture icon in the palette Lay­ers / Lay­ers and click Select Object / Select Sub­ject.

Impor­tant: you need to click on the mini-image with your straw­ber­ries, and not on the lay­er mask next to it / Illus­tra­tion: Eliza­ve­ta Lentchevicha, Photostore.Expert

A dot­ted line will crawl across the object — march­ing ants. Take a Brush / Brush and white paint over the object inside so that it becomes pure white.

7. To refine the back­ground, paint over the areas that are not being paint­ed over with a reg­u­lar black brush.

The result­ing cut object on a con­trast­ing blue back­ground / Illus­tra­tion: Eliza­ve­ta Lentchevicha, Photosklad.Expert

Thus, you can not only cut out the back­ground, but also cre­ate any mask that you will lat­er use in pro­cess­ing. For exam­ple, to recol­or parts of a pho­to.

Boost Contrast with Channels

If you raise the con­trast through one, com­mon slid­er, the bright­ness of all three chan­nels changes the same way. And often it ruins the pho­to. For exam­ple, you want to increase the con­trast in a por­trait. Skin is a red­dish col­or, mean­ing the red chan­nel will be the light­est. But the bright­ness will rise equal­ly in blue, and in red, and in green, that is, for exam­ple, the blue chan­nel will become a lit­tle brighter, and the red will turn into a sol­id white spot. Because of this, the result will be clum­sy and rough. We tell you how to get a more accu­rate and eye-pleas­ing result with the help of chan­nel-by-chan­nel con­trast enhance­ment.

1. In the palette Lay­ers click on the black and white cir­cle and click on the adjust­ment lay­er Curves. Read more about what curves are and how they work.

Illus­tra­tion: Eliza­ve­ta Lentchevicha, Photostore.Expert

2. Click on the RGB drop-down list (in curves this is called the mas­ter chan­nel, the sum of all three chan­nels). You will see a list of three curves — red, green and blue. Left click on any of them. For exam­ple, you can start with red.

Take the Fin­ger tool (also called the hand or paw) and move over the image where you want to increase the con­trast. In the case of a por­trait, it will be a per­son­’s face / Illus­tra­tion: Eliza­ve­ta Lentchevicha, Fotosklad.Expert

3. Place the foot on the light­est area of ​​the per­son­’s face. Hold down the left mouse but­ton — a point will be placed on the curve. With­out releas­ing the but­ton, lift this point slight­ly up.

Place the foot on the dark­est area on the human skin. Put a point on the curve by click­ing the left mouse but­ton, and, with­out releas­ing, low­er the point a lit­tle down.

You have increased the con­trast in one — the red chan­nel — out of three. If the col­or has changed, it does­n’t mat­ter, it will be cor­rect­ed when work­ing with oth­er chan­nels, or by rais­ing the con­trast, you can toned the pho­to at the same time / Illus­tra­tion: Eliza­ve­ta Chechevit­sa, Fotosklad.Expert

4. Repeat­ing point 3, in the same way raise the con­trast in the remain­ing two chan­nels — green and blue. If the cor­rec­tion seemed too strong for you, go through the chan­nels, adjust­ing the height of the set points, or low­er Lay­er Opac­i­ty.

Pho­to before and after chan­nel-by-chan­nel con­trast enhance­ment / Illus­tra­tion: Eliza­ve­ta Chechevit­sa, Photosklad.Expert

Read also:

Pho­to­shop for Begin­ners: How to Cus­tomize Palettes and Appear­ance

How to process a pho­to: a step by step plan

How to improve pho­to qual­i­ty: 7 ways