Sir Dcraw
This words from Dave Coffin, dcraw creator, talk themselves and are the best possible introduction to this article:
“So here is my mission: Write and maintain an ANSI C program that decodes any raw image from any digital camera on any computer running any operating system”.
Dave Coffin | dcraw
And I can assert, without risking to fail, that he is succeeding. By the moment, dcraw is the only one program that can decode any raw image from any digital camera (and, as it has been programmed in ANSI C, it can be compiled in any machine under any operative system, as I will demonstrate soon).
The matter is simple: is dcraw is not supporting a camera, only the camera manufacturer will (dcraw supported cameras). It is so, that all commercial raw developers and non commercial are using dcraw code for loading and decoding raw files in someway, and many of them includes a dcraw.dll file without embarrassing.
So, dcraw is out entrance to the world of raw developing. Just by using i as a command line raw developer, and full understanding each parameter, we will learn a lot about the technical aspects of raw developing. If you want to follow that road, I recommend you to start with Guillermo Luijk’s dcraw tutorial.
Screenshot of dcraw called without parameters
As you can see, dcraw is a command line application: no GUI. If you want to modify one development parameter you will have to develop the whole raw again with that new parameter and open the resulting file (.ppm or .tiff), that dcraw will create in the same folder that contains the raw image, with your image viewer.
It is not the more confortable way of developing, but it will give you a level of control no other raw developer will. In fact, dcraw is the only raw developer (perfectRAW also was going to) that will develop a perfectly neutral result. The rest will apply some automatic parameters for exposure, brightness and contrast. Many of them will, even if you set all controls to zero.
This is a characteristic of commercial raw developers, that try to show a first image pleasant enough for the photographer eye, and it is the main reason that makes difficult to compare different raw developers result with the same parameters. The images tend to have the “developer firm”. (Hugo Rodríguez has done the best raw developers comparison till now).
My proposal, and so of the biggest dcraw experts as Guillermo Luijk, is that you get used to a neutral result: few contrasted and few saturated. It is the best possible starting point for a successfully postprocesing and will give you more control over the final result.
So, we depend in dcraw for loading and decoding our raws and we will. But, how much quality has dcraw processing? The answer is controversial. Some years ago dcraw was giving more quality than commercial raw developers and, of course, than in camera jpegs. But, in the last months, the market of raw developing has progressed a lot, implementing more and more sophisticated algorithms, thanks to the competence between them, but also thanks to the open source and non commercials raw developers. Meanwhile, dcraw processing has stuck.
One small programmers community, to which I belong to, is putting big efforts in equiping dcraw with the best algorithms to make it compete again with commercial raw developers. This website aim to demonstrate how far is it possible.
Sir Dcraw,
Un “problema” con los reveladores creo que empieza a ser que hay demasiados y con funciones que van mucho más allá de lo que un revelador debería hacer; para lo demás están los programas de edición. Digo esto porque por ejemplo con Photivo o Darktable yo obtengo mejores resultados que con Ufraw o incluso Dcraw en consola, pero nunca tengo claro si es porque usan mejores algoritmos (de hecho ni siquiera estoy seguro de si usan algoritmos diferentes) o porque tienen tantos “agregados” que al final la imagen queda mejor por ellos que por los algoritmos de revelado raw en sí. ¿Dónde acaba el revelador y empieza el editor? Sea como sea a los usuarios que simplemente buscamos buenas fotos nos vuelve un poco locos esto de que cada 6 meses aparezca un revelador nuevo que dice ser mejor que los otros; está bien la competencia, eso mejora los producto, pero es un sinvivir, jeje, así que me alegro de tu propósito de mejorar la calidad de Dcraw, un viejo compañero con el que me gustaría seguir.
Saludos y enhorabuena por la ilustrativa web,
Comment by Carlos — July 18, 2011 - 19:16
Pues me alegro, Salva.
Comment by Manuel Llorens García — March 21, 2010 - 11:00
Estupendo, estoy muy agradecido.
Esta información me ha sido de gran utilidad para mejorar una GUI que he venido desarrollando para mis procesos de revelado y administración de imágenes.
Comment by Salva — March 21, 2010 - 03:27