Colourspaces (JPEG Pt0)- Computerphile

What's a colourspace and why do we have different ones? It's horses for courses as Image Analyst Mike Pound explains.

Professor Steve Furber on ARM: COMING SOON!

This video was filmed and edited by Sean Riley.

[goauld]

YCbCr was also used in color TV transmission for backwards compatibility with black and white tvs, because if you pick up just the Y component you can get a black and white image.

[Sarnetsky]

1:50 There's a mixup with names of color models: RGB is additive and CMY is subtractive.

[trustfulfish]

1:54 it's not additive, RGB is, CMY is subtractive - you're "subtracting" light from white making it darker.

[TamNguyenphoto]

FYI he flipped the terminology at 1:54. Additive process is RGB. YMCK is subtractive.

[CaptTerrific]

This felt like a giant teaser - when do we learn all the tricks, limitations, abilities, etc. of each color space!?

[rockstjernen]

Brilliant, thanks. CMYK is considered subtractive colours. RGB is additive. ;-)

[pypes]

CMYK is subtractive, RGB is additive

Some mention of relative gamut would be nice too :)

[lukasdon]

Can you also do a video on gammut and the different sizes of color spaces? sRGB vs. aRGB, why YCbCr and CMYK have smaller gammut than RGB, etc? Also: please explain LAB-space or XYZ-space and perhaps melissa/prophoto-RGB?

[taesheren]

Cool, looking forward to the compression/down sampling part. Will be interesting to hear what clever way they have come up with.

[MrSamurai]

This is very interesting. I, and it seems many people in the comments, would love to watch MUCH more on this topic. Almost every point he made I wanted more depth.

Keep up the great work.

[dude]

There's also HSV/HSL colour spaces. Like Y'CbCr these colour schemes separate the colour and luminance information. However, instead of have 2 colour channels, you have a hue channel (describing the colour from the colour wheel), saturation channel (describing the intensity of the colour) and a luminosity /brightness value channel (which is the grayscale brightness) . These colour spaces are used in software like lightroom and Photoshop for manipulating the colour in images

[RodrigoVzq]

This subject is really interesting to me. I am really looking forward to see more of these videos

[lakshminarayansharma]

Starting my 1st image processing course, so had to get a gist and motivation before starting the actual course. COMPUTERPHILLE ❤️❤️

[Piineapple.]

At 4:24, is it not from -128 to 127 ? I find it strange, a value from -127 to 128

[TheProCactus]

Somewhere in the middle he said the ink was additive, Its subtractive.
Light is additive :P

[jdgrahamo]

I remember a time  in art college when the lecturer asked us to predict what would happen when he shone a blue spot-light on a red screen. Very counter-intuitive!

[BariumCobaltNitrogn]

02:19 when you use cmy combined to make black it's called process black and is kind of weak and muddy. Add k (black ink) and you get true black.

[JackLe]

it is -128 to 127 because in 1 byte, there's an equal number of negative numbers and positive numbers. negative numbers start at -1 but positive numbers start at 0.

[zz]

On the model at 5:08, if luminance is zero, shouldn't the resulting colour be black (no matter what the Cb & Cr)? So the bottom plane should be completely black, right?

[AlfredoPachecoJr]

A Computerphile video on jpeg (maybe gig, tiff, etc). Can't wait. I think they already did one one how to pronounce GIF.