FIlm Simulation 3: Colour - Cross Processing

Cross processing was a nice way to tweak the colours in the original captures. Basically, slide film was processed with the standard C-41 negative film process.
Overall contrast was increased, then yellow and blue shades might appear. In general, colour was distorted - but this effect was sought-after, indeed...

Film Simulation: 2 - Colour (Theory)

The previous post showed how to produce simple B&W conversions through the use of the channel mixer with fix channel proportion values, to mimic the behaviour of specific traditional, chemical B&W films.

Film Simulation with GIMP: 1 - Black and White

OK, so we already saw how to make a black and white image out of a colour one using channel mixer in GIMP. We might select any proportion (even negative...) for each of the primary channels, Red, Green and Blue. This way, we can produce any interpretation of the original colour information.

Absence...

I know, I know. It's been already a few days since I last updated something in this blog... Neither old content (from the original posts on http://albertog.over-blog.es) nor new one. And believe me, I have new things to post...
But currently I am enganed in a couple of urgent topics, I hope you'll understand:

• I am attending a Community Manager course, I should finish it in a couple of months
• I am preparing a new book (which is NOT the update of my book on black and white conversion with GIMP). It will be some kind of "Notes on Photography", which I would use in some planned lectures over this summer... we'll see.

So don't expect many updates around here. Or maybe yes, but not related to GIMP...

Thanks for your patience.

The Bayer filter

Recently, two new camera announcements have been made, with several new features, among them the removal of the Bayer filter in front of the camera sensor.
On one side, the Leica M-Monochrom, developed to take only black-and-white pictures. This camera removes the bayer device completely.
On the other side, the FujiFilm X-Pro1 substitutes the Bayer filter by "a different one", "randomly" laid...
In both cases, cameras offer higher definition by means of the elimination of the low-pass filter... But what does this mean to simple mortals like us? Let's go step by step...

Photography: ISO Setting (Sensitivity)

Traditional (analogue or chemical) photography used different film types, with higher or lower sensitivities to incloming light. Each film type had specific characteristics and ideal application field. But digital photography has changed this, since there is no physical film anymore. However, most digital cameras still include an ISO setting - what is it for?

Photography: Aperture priority (Diaphragm)

In most cases, lack of knowledge on the broad possibilities of DSLR cameras makes amateur photographers use the automatic modes only, missing many of their creative possibilities.
One of the available semi-automated settings in most modern cameras is the Aperture or Diaphragm priority. In most cameras, this setting is indicated by an "A" letter, but there are some exceptions - Canon, for example, indicates "Av" (from Aperture Value).

Photography: Shutter priority (Speed)

One of the most useful setting mode in DSLR cameras is seldom used by amateurs, mainly due to poor information on its possibilities.

This semi-automated mode, indicated by a "S" (for shutter) or "Tv" (in case of Canon, from "Time value") sets the time that the shutter is open. This way, we can decide how long will light be entering to the sensor surface. This setting can be adjusted (depending on brand and model) from 30 seconds down to 1/8000th of a second in some professional cameras.

Fake HDR with GIMP

Since a few years already, a trend in photo edition is the increase of the dynamic range of pictures (HDR - High Dynamic Range). It is the way to use all available sensitivity range of the camera, or even to go some steps ahead by combining several images, taken with different lighting settings.

Depending on the image, the process can be quite complicated, and itis based on the identification of zones with very different lighting levels, a "local development" of each area and a composition (zone mapping) that produces a credible merging of all areas.

A new Android App: booX

 
A group of Computing students of Valencia University is about to launch an Android App for books interchange. Its name? booX. You may leave your email address at http://ooomf.com/boox so that you will get a notice when it is released...
From the beginning, it will be available in multiple languages, thanks to the collaboration of many friends. And I am proud to anounce that the initial logo design comes from me - what do you think?

Publicado simultáneamente en Over-Blog

GIMP - Curves adjustment

One of the easiest and more powerful adjustments in graphic edition is the curves adjustment. However, lack of clear, simple indication has made users afraid of trying it... let's try to fix this.

The concept
First thing you have to make up your mind is colours. White is white, black is black. Then, a 50% grey is a 50% grey. Simple, ain't it?
OK, then open any image in GIMP. You can launch the curves tool through "Colours -> Curves...", either from the upper menu or by clicking the right button anywhere on the image surface.

Types of Histograms

Well, from the previous post, we already know what the histogram is. Now, let's check what are the most frequent histogram types, and how can we use them in photography...

Types of histograms
Usually, the histogram of our pictures will look like one of the following:
 Histogram #1: uniform distribution on all tones, a slight maximum in the central ones. In this case, the image would have a rich variety of mid tones (or grays), and besides (in this example...) it also includes the extreme values for black and white. Opposite to what you may think, this kind of images might result too soft and lacking interest (except in the case of HDR, but that's another story...).

The Histogram

In most internet forums and webpages on photography, sooner or later you will read about histograms. Some photographers use them as a reference to evaluate their photos upon shooting, in order to make minor modifications to their camera settings. But, what is a histogram?

My coin box...
After looking for different definitions, I did not like any of them... So please forget about photography for a moment. Let's take a look at my coins box...

What is EXIF data?

With the introduction of digital photography, several improvements have been added to photography. Among them, the addition of Exif information in the electronic image files. This article describes what does this information contain...

Creative bokeh

Interestingly, one of the most visited posts in this blog is the one related to Bokeh. As I indicated, this is becoming the next trend, and once people is learning how to control shutter priority or aperture settings, they are starting to investigate deeper in the creative possibilities of (DSLR) digital cameras...

Bokeh (EN)

With the current booming of DSLR cameras, you can read more and more about bokeh in magazines and technical webs. What is it, and how can you use it in your photos?
Bokeh (from Japanish boke) refers to the blur obtained in pictures far from the focused area. This blur depends on several parameters, which gain in importance in DSLR cameras; among them:

Photographic crafts (opinion)

As it seems, I am becoming outfashioned - again. I keep on taking photos with my DSLR (a digital Canon 500D, wich provides real vision through the penta-mirror - not penta-prism), working on composition, lighting... and then, doing some later post-processing.

Even when I used Photoshop, it is not really inside my budget (at least, until I can work as a pro with photography...), so currently I am using GIMP, quite similar for most of the usual processes. With time, I could improve my technique, and I am preparing a book, which I hope to publish within this year.

But I take a look around and I can see everyday anouncements for new cameras with advanced automatic modes, and even cellphones capable of taking quite reasonable photos, applying creative effects on the fly...
So I picture myself again as a library rat - or rather, a photolab rat, in this case. The revival of film photography, even just as a curiosity, won't change this. There is a majority of people interested in point-and-shoot photography, in capturing moments regardless of the result quality.
Anyway, as long as this situation won't change much, I will keep on carrying my camera around, almost everywhere I go. And, if time and family allows me to, I will keep on spending long hours in front of my monitor, balancing lights and colour, and finding the right crop for my pictures...

Originally posted: Feb 8th 2012

A new beginning...

Here you have a new beginning for my blog... After starting with Wikio and spending some time with Over-Blog, I decided to take control of my posts.
I don't expect to become rich out of this, but at least I will not let others become it from my work...
Little by little, I will transfer all contents from Wikio and Over-Blog to this site: you will be able to see my progress in a short time... and, of course, I will add new contents here, so don't slip up!