[Only registered members may post.] [Threaded View] [Translate]
Tonemapping karith Gold Star Critiquer/Gold Star Workshop Editor/Gold Note Writer [C: 1037 W: 55 N: 1262] (7891)::2008-09-07 10:45
Could someone explain tonemapping to me? I've come across that term but don't know what tonemapping is all about or how it works or when to use it. Thanks.
Re: Tonemapping SunToucher Gold Star Critiquer/Gold Star Workshop Editor/Gold Note Writer [C: 1376 W: 234 N: 1593] (8380)::2008-09-07 10:54
As far as I know,its the part of the Photomatix HDR technique that makes the HDR back into a photo. its where you make the adjustments to map the tones (color and contrast) captured in the HDR.
Niek
Re: Tonemapping karith Gold Star Critiquer/Gold Star Workshop Editor/Gold Note Writer [C: 1037 W: 55 N: 1262] (7891)::2008-09-07 19:05
Thanks, Niek. I guess I need to look into this further:)
Re: Tonemapping appalcarp Gold Star Critiquer/Gold Star Workshop Editor/Gold Note Writer [C: 1101 W: 154 N: 633] (4198)::2008-09-09 14:42
Karen, as Niek said, it has to do with HDR. For example, you have a picture of a black cat against a fairly light background (sleeping on a tan blanket, for example), so you take two pictures, one for the background and one for the cat (using tripod if possible). Then by combining them you get the 'true' way that the human eye naturally perceives them because most cameras will either use the lighter bg or the darker subject depending on your setting. By then combining the images, you get what the human eye either does or 'should' perceive. In other words, the cat's hairs and the reflections of them would be preserved as well as the folds and dark/light areas of the blanket which naturally occur from the lighting source(s).

I've used the Photomatix (free) version but it's very basic and now puts a watermark on the picture so if you want the option and your software doesn't have it, you may have to spring a few pennies/quid/Euros, whatever. If someone knows something I haven't investigated, please post a link for the free-type software.
Re: Tonemapping Art_R Silver Star Critiquer/Gold Note Writer [C: 30 W: 5 N: 75] (458)::2008-09-10 10:55
Hi , there are not very many free programs for true HDR but a couple that I have found

one is called cinepaint I believe that another name it was called by is 'film gimp' , it is an opensource project , and like many opensource it was developed in the Linux operating system. presently it is only really a program to watch for in the future , I believe there is a mac and linux stable release but for widows only a beta version , it is meant for program developers.

here is a url for a bit of reading :-)

http://www.cinepaint.org/docs/br2hdr/HDR_Tutorial-en.html

on the techno babble side but still has some good info , I would not run that program as a beta , waiting on a stable release is good. I prefer to see more than one stable release.

a second opensource HDR program is Qtpfsgui , but I would not let a name fool me :-)

http://qtpfsgui.sourceforge.net/about.php

opensource is free , but also it is good to know that there is also a greater chance of encountering program bugs and glitches. however there are some amazing opensource projects , the GIMP being one of my favorites. opensource is not for the faint of heart ,like TL it is a community , if a program freezes or crashes it is not 'paid for software' there is no one to complain to , only the option to submit a bug report for the developers to fix it. there is a certain element of risk running opensource software. when searching out opensource it is good to keep in mind your OS , a search for the GIMP for example would be 'Gimp for windows' most opensource is Linux and many never make it on to the windows platform.

tone mapping is the process where a hdr image is converted in to an ldr or low dynamic range image. a true hdr image is 32 bit image , and a computer monitor is not capable of generating enough colors to display it , the same goes for most printers , so it is converted to a usable bit depth , by tone mapping.

I must admit myself to being somewhat baffled by hdr :-) why bother ? if it is not a usable file ?

LDR on the other hand makes some sense to me exposure merging can do some neat things , and not only with multiple exposures , the same technique can also apply to a single raw file , or even in a pinch a single jpeg.

http://www.instructables.com/id/HDR-photos-with-the-GIMP/

I have been playing around with this instruction set , though it uses the term HDR , in truth the process is LDR often terms are confused with process , the gimp is not capable of working in a 32 bit color space so it is not really the same as HDR that most are referring to. the process uses jpeg files.if I am not mistaken this process when used in CS3 is a HDR process , I am not certain though it depends on being able to work in layers of tiff files instead of jpeg , when I tried in PS elements6 it gave me a pop up saying something about CS3?

hdr and ldr are a bit confused as well , it seems to depend on who is doing the explaining as to what is what. in the strict terms hdr is a 32 bit floating point image , which refers to how many colors the image is able to describe. but looking around one can find that a 14 bit raw file may also be termed as a hdr , and a 16 bit tiff as well

the same goes for ldr ,

I think that just thinking of it in terms of what can display on a screen (or printer ink) and what can't is good enough.

I also tried photomatrix and the Qtpfsgui program ,and really was not fond of either , but the gimp instructions are kind of neat , and shows how to use layers and layer masks to make adjustments to certain areas of a photo . it is a very hands on approach.

regards
Art
Re: Tonemapping appalcarp Gold Star Critiquer/Gold Star Workshop Editor/Gold Note Writer [C: 1101 W: 154 N: 633] (4198)::2008-09-11 12:00
Thanks, Art.

One other thing with the hdr from Photomatix is that the files have to be EXACTLY the same size for it to work.
Re: Tonemapping SunToucher Gold Star Critiquer/Gold Star Workshop Editor/Gold Note Writer [C: 1376 W: 234 N: 1593] (8380)::2008-09-11 23:35
Gary,
What do you mean with size? Do you mean file size or pixel size? If the latter, you are correct, but that is pretty obvious when you make one photo our of mutiple.
Re: Tonemapping appalcarp Gold Star Critiquer/Gold Star Workshop Editor/Gold Note Writer [C: 1101 W: 154 N: 633] (4198)::2008-09-12 14:53
Niek, I used the free version and the pixels on each side had to be exactly the same. So if it was 800x600, the other one also had to be, at least in the version I had, that's the way it was, maybe I missed something in their instructions.
Re: Tonemapping SunToucher Gold Star Critiquer/Gold Star Workshop Editor/Gold Note Writer [C: 1376 W: 234 N: 1593] (8380)::2008-09-13 1:12
Now I understand you used a croped version of a photo to make an HDR. Its much better to use the original versions and when you're done do a crop.
Re: Tonemapping appalcarp Gold Star Critiquer/Gold Star Workshop Editor/Gold Note Writer [C: 1101 W: 154 N: 633] (4198)::2008-09-13 4:54
When doing a light/dark with a tripod, for example, that would work, but in the situation I was working in, I wanted parts of two specific scenes. I think I'd like to get the 'regular' version, however, it might be more conducive to those types of modifications.
Re: Tonemapping SunToucher Gold Star Critiquer/Gold Star Workshop Editor/Gold Note Writer [C: 1376 W: 234 N: 1593] (8380)::2008-09-13 5:08
Sorry, I don't get it. You were trying to do a HDR of different scenes? That won't work, even in the full version. Its all about the dynamic range of a singe scenery either captured by bracketing the shot or by converting different exposures of the same RAW.
Re: Tonemapping appalcarp Gold Star Critiquer/Gold Star Workshop Editor/Gold Note Writer [C: 1101 W: 154 N: 633] (4198)::2008-09-13 18:08
I was trying for a 'double image' overlapping effect, strictly pp, ya know.