VFX Worf flow - colour correction

Hello guys ,
I am back with another important concept of the vfx work flow .
That is "Colour Correction " .Also called as color grading .
Color grading , is the process of altering and enhancing the color of a motion picture, video image, or still image either electronically, photo-chemically or digitally. The photo-chemical process is also referred to as color timing and is typically performed at a photographic laboratory. Modern color correction is digital color correction .
To underastand color correction easily ,i will give you a simple example .In lots of movies we might have seen many night effects shots .Actually the majority night effects are computer generated colour corrections .They were shot in day time .later the vfx team will change the colors .observe the following picture .

day to night conversion image :

In compositing work flow ,color correction takes major part. why because ,After compositing blue matte or roto extracted parts with some different back grounds,it looks artificial due to color grade differnece between each layer (image/ video) .To OVERCOME THIS PROBLEM VFX ARTIST should have to color correct the foreground and background images to get realistic output .see the following images .

color correcting the composited image :


To become a good color grading artist ,you should be familiar with color theory .i will explain color theory briefly .
the color wheel ;

The color wheel or color circle is the basic tool for combining colors. The first circular color diagram was designed by Sir Isaac Newton in 1666.
The color wheel is designed so that virtually any colors you pick from it will look good together. Over the years, many variations of the basic design have been made, but the most common version is a wheel of 12 colors based on the RYB (or artistic) color model.
Traditionally, there are a number of color combinations that are considered especially pleasing. These are called color harmonies or color chords and they consist of two or more colors with a fixed relation in the color wheel.
ColorImpact is designed to dynamically create a color wheel to match your base color.
Primary, Secondary and Tertiary Colors
In the RYB (or subtractive) color model, the primary colors are red, yellow and blue.
The three secondary colors (green, orange and purple) are created by mixing two primary colors.
Another six tertiary colors are created by mixing primary and secondary colors.

COLOUR CORRECTION TUTORIALS COMING SOON

vfx workflow- blue green matte compositing

BLUE/GREEN MATTE :

Hello guys now i am going to tell you about another major technique in visual effcts industry. that is chroma key .you might have seen many movie making scenes with green or blue screen in the background .what they will do with those blue and green screens ?? how they useful to add the special effects ??
i will clarify your doubts .this is for the beginners and newbies to the vfx industry so i am not going into use any technical terms .i will give you a brief idea about chroma key (blue/ green screen keying) .

Chroma key compositing, or chroma keying, is a post-production technique for compositing (layering) two images or video streams together, used heavily in many fields to remove a background from the subject of a photo or video.
 A color range in the top layer is  made transparent, revealing another image behind.

Why green and blue backgrounds are more commonly used ?

because they differ most distinctly in hue from most human skin colors.
This keyer technique mostly used y all the national and international news channels and live TV shows.

 wherein the news presenter appears to be standing in front of a large map during live television newscasts, though in actuality it is a large blue or green background.

If the news presenter wears blue clothes, his clothes will also be replaced with the background video.that is .no part of the subject being filmed with the color (blue/green) used in the background. 

The chroma keying technique is commonly used in video production and post-production also. This technique is also referred to as color keying, color-separation overlay,

Chroma keying is also used in the entertainment industry for special effects in movies and video games.
you knew about Roto (If not please refer my previous post),  Suppose Director would like to film a scene in the amazon forest with main lead of the movie  .it is very expensive and tough  shot .where another alternative for this is  Rotoscoping.
.after the shot we can Roto for all the cast(selected parts of the frame as per the director guide lines) and we can place amazon forest background images or videos .but again here Roto is time consuming process .the very good alternate for this is Chroma key .
 To use the blue/green screen technique, we have to film the amazon videos (footages ) on location. This shot is called the background plate.

 Then we have to film the main cast sequences as per the script in front of blue/green screen in a studio(or in any affordable location).

The chroma key technique lets you combine two or more pieces of film into one piece that looks very real.
You end up result look like this:

As the availability of many vfx softwares computer software, such as Pinnacle Combustion,after effects, Adobe Premiere, and dozens of other computer programs, makes it possible and relatively easy for the average home computer 
user to create videos using the "chroma key" function and easily affordable green screen or blue screen kits.
Thank you , will be back with next concept from the vfx work flow .

ROTOSCOPING (ROTO) :

Let us start with primary and very important concept in vfx work flow.
Roto is a process of extracting the areas of live action shot to compose with computer graphics (such as sky replacements ,bg changes ,effects and many more) with in the frames,Roto gives transperent areas (mattes) within the frame to allow placing special effects and/or 3d environments .

observe the following images before and after Roto .

Roto is a primary and important work in the vfx department .
but Roto will be an entry level job,it is the most junior role in the Compositing Department particularly suitable for the freshers.



This will offer a good opportunity to gain professional and practical  experience and learn more about production work flow and techniques .once fresher got the good experience in junior level ,he can apply for a better post in future .
Depending on the production work flow designed by a company ,The Roto Artist should work on Fusion ,Nuke ,Silhouette, Mocha , Shake, Combustion or After Effects.having good knowledge on all the above softwares will be added advantage .

key skills to become a good Roto artist .

1.Patience.
2.Command over softwares.
3.Understanding  color theory.
4.Drawing skills and fine arts back ground would be great advantage .
5.Willingness to address comments and make changes.
6.Drawing skills including good line quality .

News :Roto tutorials will be added very soon .KEEP ON FOLLOWING THE BLOG .

overview of visual effects - 1

overview of visual effects - 1

what are (VFX) Visual Effects) :

VFX ,Visual Effects are imagery effects created outside the context of live action shoot .which involves the integration of live action footage and computer generated back grounds ,Scenarios and creatures which look realistic but would be dangerous,costly or  impossible to shoot .the film makers are considering vfx as major part of their big budget films.some great examples would be Avatar , 2012, Green lantern,Ghost rider,300, John carter ,Wrath of titans , Journry2 ,Pirates of the Caribbean, Harry potter series ,Iron man series and many more vfx based movies are going to hit the screens .is it possible to shoot earth quake shots in 2012 movie with a camera?? no, all these are directors imaginations.highly impossible to filming these imagery concepts. but you can create these kind of effects by using animation and composting software through a computer, called computer graphics .this various processes are called visual effects .
the term vfx is very easy to spell, pronounce and write .but this includes many techniques ,time and man power .i am going to explain you each and every topic in the visual effects process happening in production studios .This article helps to the people who want to know more about visual effects and the people who wants to make vfx as their career . Let us see some vfx movie trailers,you will understand and follow me easily .

CAREERS IN VISUAL EFFECTS :

These days vfx has become a very good career option for aspiring candidates. it does not need any qualification ,if you have a good qualification it would be a added advantage . as a experienced vfx artist and trainer ,i have met many students who were not satisfying with the course content because they did not choose suitable part of vfx.what they expected is complete different from what they were learning. this article will give you complete description about vfx work flow ,concepts and career options for freshers and experienced .the people who are going to choose vfx as their career , go through the complete article and then decide which module is suitable for you .good luck .
note: i will post topics one after the other .please do follow the posts .feel free to ask about anything in multimedia ,animation, vfx
STAY TUNED to get more updates on visual effect complete overview next parts.