How were the term Levels & Curves made ?

dakoo · Joined: 08 Mar 2008 Posts: 603

Does any one know of this ?
I am trying to find a hindi/marathi (languages in India) word for it.
Does anyone know of it.

Orio · Expire: 2012-12-04

Level comes from the Latin word Libellus = small book.
The reason is because it has originally a legal meaning. The Libellus was the contract for which a good was rent to other people for they could make a profit. Example, renting a field so that you can make a crop. So the contract was made to make the profits equal and was recorded on a small book (Libellus)

Curve comes from Latin verb curvare = to bend.

dakoo · Joined: 08 Mar 2008 Posts: 603

sichko · Joined: 20 Jun 2008 Posts: 2475 Location: South West UK

I'm not sure when or how the terms were originally used in photography. However here's a guess.

Level can mean the height of something. So if we have a multi-story building the different floors are at different heights relative to some reference - we say they are at different levels. If we look at the histogram on the back of our camera, or in photoshop or some other program, we see a series of 256 lines, numbered 0-255. The height of each line is proportional to the number of pixels with a particuar intensity. So if the line at the extreme left is extremely high we have a lot of black pixels, and so on. We could talk about the relative heights of the different lines. Instead we use the word levels. I don't know why - and remember it's just a guess.

Curves. I don't use Photoshop but in the program I use there is a picture of the histogram with 3 sliders at the bottom. There is also a black line running from the bottom left corner to the top-right. If I move the slider at the left (black point) and/or the slider at the right (white point) the line moves but it stays straight. If I move the slider in the middle it becomes curved. Coincidence ?

Nesster · Expire: 2014-02-20

Curves is associated with the film "characteristic curve" - exposure/density, spectral response.

cooltouch · Joined: 15 Jan 2009 Posts: 9096 Location: Houston, Texas

Hey Sichko, sounds like you and I use the same image processing software -- Paint Shop Pro. I'm using X2 after using v8 for years, and find I don't need Photoshop at all.

I have always assumed that "Curves" refers to the ability to manipulate the histogram, which is a curve (mathematically speaking, more or less) when the colors are combined or a set of three curves when they are not.

As for "Levels," I think more in terms of 'limits', since one is truncating the ends of the curve and adjusting the mid-point.

From a pragmatic point of view, however, I don't find much difference between the two functions -- at least in PSPX2 -- and usually use the Curves function. However, if I am having some difficulties with an image, I'll give Levels a try too to see if I fare any better.

visualopsins · Expire: 2025-04-11

I think OP wants someone with Hindi version of Photoshop to tell him what Adobe says is Hindi for levels & curves functions. Or perhaps at local camera shop someone uses Photoshop can say what they call functions.

dakoo · Joined: 08 Mar 2008 Posts: 603

dakoo · Joined: 08 Mar 2008 Posts: 603