Highlights, Midtones & Shadows

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H and M Video
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Joined: Jun 5 1999

Feel a bit stupid asking this question but in colour correction programmes there are adjustments for Highlights, Midtones and Shadows. A photo or video is 2D so what do these apply to and which is which?

Harry :confused: :confused:

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Alan Roberts
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Stills are spatially 2d (h and w), but are colorimetrically 3d (r g and b, or H L S, or Y U V etc) as well. Video has a temporal dimension as well as that, so is 6-dimensional, stills are 5-dimensional*.

Simply, Highlights means bright parts, near white, Shadows means stuff near black, Midtones mean stuff in the middle. Pretty much what you'd expect.

*I usually think of colour as being 77-dimensional, meaning a separate dimension for each 5nm-wide wavelength group from 380 to 760nm, but video and film does a iso-meric to meta-meric conversion, to shrink it to 3-dimensions. It works provided you have normal colour vision. But I digress..... :D

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Dave R Smith
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Joined: May 10 2005

Best bits of Match of the day, a Punk group and Cliff Richard.;)
Or
White or Bright pixels (often sky), mid tones? and dark.. oh boll*x Alans beaten me...

Alan Roberts
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You gotta be quick 'round here :D

Get my test cards document, and cards for 625, 525, 720 and 1080. Thanks to Gavin Gration for hosting them.
Camera settings documents are held by Daniel Browning and at the EBU
My book, 'Circles of Confusion' is available here.
Also EBU Tech.3335 tells how to test cameras, and R.118 tells how to use the results.

Claire
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Joined: Apr 28 2001

Some colour correctors that have independant black, mid and white adjustment such as exists in Edius can be used not only to adjust colours in those specific areas but also the luma level (contrast) so that black crush or stretch can be applied, or mids boosted without burning out whites, etc and of course to legalise peak whites in a more refined way that simply throwing a clamp on and just clipping blacks & whites.

Previously I would have used YUV curves for this task in conjunction with waveform/vectorscope but these days I prefer to do it with Edius's "White Balance" tool which to my mind is not well named at all since it does all these things and much much more.

I suppose these tools will be in most decent NLE's these days.

Claire

H and M Video
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Joined: Jun 5 1999

Thanks folks for the enlightening replies. Now I know that I am not stupid but that I am technically deficient. :o

Harry

PC Specialist 3Gz Dual Core, Premiere CS3, Encore CS3, After Effects CS3, Matrox RT.X2, Panasonic HD HS-300, Z1E & PMW-EX3 Cams.
 
Now with a PC Specialist Quad Core i7-3770, 16GB RAM, 180GB SSD, GeForce GTX560 Ti Graphics Card, Blu-Ray & DVD R/W Burners and can't wait to set it up. Now up and running.  What a difference in Blu-Ray footage.

Alan Roberts
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I agree about Edius' capabilities, very impressive once you get to grips with it.

Get my test cards document, and cards for 625, 525, 720 and 1080. Thanks to Gavin Gration for hosting them.
Camera settings documents are held by Daniel Browning and at the EBU
My book, 'Circles of Confusion' is available here.
Also EBU Tech.3335 tells how to test cameras, and R.118 tells how to use the results.

Chris.
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Joined: Nov 5 2000

You can get a very practical idea from still photography software like Photoshop, in particular the levels adjustment and the corresponding histogram

http://images.google.co.uk/images?source=ig&hl=en&rlz=1G1GGLQ_ENUK266&q=photoshop+levels+histogram&um=1&ie=UTF-8&sa=N&tab=wi

Dave R Smith
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Joined: May 10 2005
Chris Longley wrote:
You can get a very practical idea from still photography software like Photoshop, in particular the levels adjustment and the corresponding histogram

http://images.google.co.uk/images?source=ig&hl=en&rlz=1G1GGLQ_ENUK266&q=photoshop+levels+histogram&um=1&ie=UTF-8&sa=N&tab=wi

Many stills and video cameras now display histogram of levels, so for those not used to seeing them, after experimenting with likes of photoshop 'levels', it can improve your art at source by checking your shots..... so it's not just a pointless gizmo for the geeks.;)