Archive for October, 2006

Playing with a scanned picture

30 October, 2006 Leave a comment

Installing a scanner on linux

Since going back in Toulouse, six months ago, I never took the time to reinstall my good old hp scanner. So I did it, it’s really nice to see how linux has improve in the past few years, about a year or two ago, I would have to spend more than an hour to figure out how to configure my linux box to recognize the scanner, now it’s really “plug and lets the fun begin”.

The actual playing

I am still a little bit old fashion when it comes to photography. But the digital camera (even the best one) aren’t even close to the quality and the feel of my silver-film reflex camera. Especially when it comes to black and white pictures. I still have a digital camera to take all the pictures without considering how costly is silver-film.

And from time to time I like to have a digital version of my picture, but even if the starting picture is nice, the result after scanning is awful:

Thanks to “autocontrast”, the result looks slightly better:

I am sure that even better results could be achieve using brightness/contrast curve, but I didn’t took the time to tweak the results more. Beside brightness, the image looks a little bit blured.

Lets try the “sharpen” filter:

Lets use the cancel menu… The result is so bad. Lets try the “unsharp mask” (weird name for something that is supposed to increase the sharpness of an image) filter:

Now, I really understand why a lot of people wanted the “unsharp filter” it gives pretty nice result considering how simple it is to implement it. Even if there are better algorithms out there, but they are harder to implement.

As you can see there are some hole in the lake caused by dust on the window of my scanner, they are easily removed with the duplicate tool.

I wanted the final results to looks like old postcard (with sepia tones), so I took the “color adjustment filter”, I have increased slightly the quantity of red, green and decrease blue, like in the following screen shot:

And the final result of this picture taken in the Andoran mountains:


It’s really funny…

18 October, 2006 2 comments

… wether a graphics application support CMYK or not, each time there is an article about this application, there is a lot of comments around CMYK. Each time, the gimp has released a new version, someone would ask “do this,at last, support CMYK ?”, or if the question “what application do you miss on linux ?” is raised, someone will answer photoshop because of its support of CMYK.

So now, krita supports well CMYK since 1.5 (actually some CMYK support was introduced in 1.4, but as a demo), Monday, we have release a new version, and I can see some comments about how useless it is to support CMYK (wether it is on slashdot or the dot).

I am thinking that the emergence of the opinion about the uselessness of CMYK, has start, recently, by an interesting comment of Nathan Willis answering someone who was wondering if GEGL will bring CMYK support to the Gimp. And I think he is correct, in 99% of the use case, users won’t need CMYK at all.

So, is CMYK really the reason preventing people to use Open Source image editors ?

While CMYK (Cyan Magenta Yellow blacK) inks are used by all color printers, all home and business printers do the conversion from RGB alone. Which means, that, most of the time, if you create an image in krita (or photoshop) in CMYK, you will gain nothing, because krita will have to convert it to RGB before printing!

So useless feature ? In fact no, some professional printers like, for instance, offset printers takes CMYK as input. When I was still studying in engineering school, I took care of editing and printing the student newspaper, and we were using duplicators (we had much more modern version…), we had two of those machines, a one-cylinder duplicator (which could create the master) and a two-cylinders one (but which was requiring the first one to create masters), we were able to emulate CMYK printing, by printing twice with the two-cylinders machine, but as the master could only be created one at a time, we needed a CMYK capable application to do manually the printing.

That’s why, Marc and Marie are the only two people who need a CMYK editor. Marc is working for a professional printing service which own printers whose drivers works in CMYK (assuming such a driver exist on linux…). And Marie is an artist, drawing original artwork from scratch and she ask Marc to print them. While John is a photograph, he also send pictures to Marc for printing, but it’s camera creates RGB images, so there is no difference if he transform the image himself, of if he gives Marc directly the RGB images. For Marie, CMYK editing is important, because it will give her the most control on the resulting image, mostly because C=M=Y=100% B=0%, and C=M=Y=0% B=100% is the same color, black, but when printed, the second one will looks better than the first one. But all other people in the world are in the same position as John, they don’t care about CMYK.

So except for Marc and Marie, CMYK is not the reason why people will choose Photoshop over the Gimp, or Krita over the Gimp. Supporting CMYK is a nice feature, that some people need, but it’s not breathtaking and it’s far to be the most useful feature of an image editor.

KOffice 1.6 Final !

16 October, 2006 2 comments

The version 1.6 of KOffice has been released today. With a lot of new stuff to check, including:

  • in krita: perspective framework, layer mask, magnetic selection, a lot of new filters
  • in kexi: a lot of improvement in the UI, a new data type : Images.
  • in kormula: the best support of OpenDocumentFormula/MathML

And many more, as you can see in the official announcement.

I have made a KOffice Live CD if you want to test this new version.