Image Channel Extractor
Pull a single channel out of an image and save it as its own grayscale picture. Choose red, green, blue or alpha, and the tool returns that channel with bright pixels where the channel is strong and dark pixels where it is weak. Handy for inspecting color separations, building masks from transparency, checking compression artifacts or preparing textures for games and 3D work.
Frequently asked questions
What does the extracted image show?
It shows the values of one channel as shades of gray, from black for 0 to white for 255. A red channel image, for example, is bright wherever the original contains a lot of red. The output has the same dimensions as the source.
How do I get a mask from transparency?
Choose the alpha channel. Fully opaque areas become white, fully transparent areas become black and soft edges become shades of gray. This mask can be used in editors, game engines or compositing software.
Why do I get an error when I choose alpha?
The uploaded image has no alpha channel, which is always the case for JPEG files and often for PNG files without transparency. Choose red, green or blue, or upload an image that contains transparency.
What happens with a grayscale image?
Grayscale images have one color channel, so red, green and blue all return the same gray image. The alpha channel of a grayscale image with transparency can still be extracted.
What is the output format?
The channel is saved as a lossless PNG with equal red, green and blue values, so it displays as grayscale everywhere. No transparency is included in the result.
What are channels useful for?
Single channels help to find noise, which is often strongest in blue, to judge exposure per color, to create masks for selections, and to pack separate grayscale maps such as roughness or metalness into textures. Photographers also use the red channel as a quick black and white conversion for portraits.
Can I put channels back together?
Yes, the Image Channel Merger joins three or four grayscale images back into one RGB or RGBA image. Extracting, editing and merging channels gives full control over each color separation.
Which formats can I upload?
Upload JPEG, PNG, GIF, WebP, TIFF or AVIF files up to 5 MB. Animated files use their first frame and images over 4000 pixels on a side are scaled down to fit.
Are the values exact?
Yes, the channel values are copied as they are after decoding, without any color conversion or adjustment. Each output pixel equals the 8-bit value of the chosen channel.
What engine is used?
The tool uses the extractChannel operation of the sharp image library. Processing is deterministic and fast.