Sunday, 11 September 2011

Non-Destructive Image Editing - 3



    1.    What model does cataloguing software use ?

These programs use a library model for their structure.

  1. Where are the images stored in a catalogue based system ?
The files are stored in a single folder, in multiple folders, or even across multiple hard drives.

  1. Where does the catalogue get its initial information about the files ?
Software has collected all the metadata about the photos in a central location—and because the software can create new meta­data as the user deems necessary—the catalog becomes a versatile place to know about entire collections, and to control and manage the photos.

  1. Where does the cataloguing software store this information ?
It’s natural fit for cataloging software and non-destructive imaging to grow together, storing the software in programs like Apple Aperture and Photoshop Lightroom.

  1. What is the main organising principle of Browser based systems ?
It never uses the database as a place to save information. File browsers merely cache information in their databases. That is, they stash it there for quick access but always look to the original source file to see if the cache is up to date and correct.

  1. How do cataloguing systems organise their images ?
With cataloging software the informa­tion about the photo is assumed to be most accurate in the catalog, rather than what may be residing in the file itself. Of course, much of the information came from the file originally and can be pushed back into the file when desired.

  1. How does a cataloguing system make changes to an image ?
When you make a rendering change to an image with catalog-based PIE software, you are changing the information in the catalog and in the preview that gets cached, but you are not necessarily touching the original file.

  1. Can other programs see these changes ?                         
Yes

    9.   How does a cataloguing system make changes to an image available to other programs ?

If your library is made up of DNG files, you can push an embedded preview back into the DNG file. This semipermanent fixed rendering can make the adjustments visible to any program and remains embedded in the source file itself for easy management.

  1. List 5 advantages of Cataloguing based PIE software ?

    1. Simplifies organizing
    2. archiving of photos
    3. Information can be created, stored, and cross-referenced in a single environment
    4. Multiple renderings can be attached
    5. saving of multiple versions

  1. Give two examples of software that combine Image Cataloguing and Editing functions ?
    1. Apple Apeture
    2. Lightroom

Sunday, 4 September 2011

NON DESTRUCTIVE IMAGING TUTORIAL




1.       Open the image NDE-1.tif in Adobe Camera Raw and do the following :-
i.         Use the Straighten tool to straighten and crop the image.
ii.        Adjust the colour temperature.
iii.      Adjust the Basic controls to give good rendition of the view outside the lighthouse.
iv.      Use the HSL/Greyscale control panel to make the orange rocks and foliage slightly more saturated.
v.        Use the Local Adjustment Brush to lighten the floor and ceiling to reveal a little more detail in these areas.
vi.      Use a second soft Local Adjustment Brush to brighten the light lens and add a yellow colour to it.
2.       Open the image into Photoshop as a smart object.
3.       Use ‘File->Place…’ to add NDE-2.tif as a smart object into the image. (Press enter when the image appears.)
i.         Flip the new layer horizontally so the photographer is facing in the opposite direction.
ii.        Resize the new layer to make it a bit smaller.
iii.      Remove the background from the new layer by creating a layer mask. (There are a number of ways to do this).
iv.      Move the photographer into an appropriate position at the bottom of the frame, and resize if necessary.
4.       Double-click on the NDE-1 icon in the layers panel to open it in ACR.
i.         Make a change and resave to see the effect.
5.       Double-click on the NDE-2 icon in the layers panel to open it in Photoshop.
i.         Make a change and resave to see the effect.
6.       If you have worked Non-Destructively throughout this exercise you should be able undo or modify any of the editing changes you have performed.

Non-Destructive Editing Commands

Non-Destructive Image Editing 2


Part II – The Rendering Engine

What is a Rendering Engine ?
               
The color information in the raw file needs to be sent through a rendering engine to be
turned into standard RGB color. 

 What three things determine the final colour of an image pixel ?

 original image data
settings applied by user             
rendering engines math formulas

What are the three main components of a RAW file ?

jpeg preview
metadata
mosaiced RAW image
Can PIE software be used only on Raw files ?             

       No. 
PIE software is now being used on source images that come in to the
program as fully processed RGB images, such as JPEGs or TIFFs.

What is a Live Rendering ?

       A temporary preview, before it becomes permeant 

Where can the Rendering Metadata be stored ?

XMP data
sidecar file
 database

Give two examples of a Fixed Rendering
derivatives 
prints

 Is a Preview a Live or a Fixed Rendering of the image ?

They are Fixed.

Where can Previews be stored ?

RAW files
 data base
 file browser

Why do File Browsers and Cataloguing software create Previews ?


To speed up the display

        

Monday, 29 August 2011

Non-Destructive Image Editing

Part I – The Evolution of Non-Destructive Imaging


Define ‘Non Destructive Imaging’

In general, NDI refers to imaging processes where the source image may be adjusted in
a way that leaves the original data intact.


List four challenges introduced by digital photography :-
  1. The creation of a vast number of photos
  2. The need to apply identical adjustments to many photos in one operation
  3. The need to interpret a single source image in multiple ways (black andwhite, and color, for instance)
  4. The desire to take advantage of rapidly evolving imaging technology to reinterpret images with more capable software in the future
What is meant by a ‘Derivative File’ ?

You might have an exact duplicate of the photo file—a copy—or you might have
a version of the photo file that has had some adjustments incorporated—which we will call a
derivative file, since it’s derived from the original.
 

What are two problems with using ‘Save As …’ to create derivative files ?
  1. might be hard to sort out later.
  2. in terms of storage.
What is ‘Self Referenced Non Destructive Imaging’ ?


In Photoshop 3, layers were introduced and it became possible to save multiple versions 
of the same image within a single file. This helped with the management difficulties associ-
ated with derivative file workflow but did nothing to address the storage needs. In Photoshop 4adjustment layers were introduced, and it became possible to wrap up the source image with a set of instructions (or many sets of instructions) for rendering the photo. Let’s call this 
self-referenced NDI.


List two advantages of Self Referenced NDI over the use of Derivative Files :-
  1. Using self-referencing files offers some significant advantages over derivative file workflow. Since the instructions to adjust the image take up much less space than creating an additional file, it’s much more economical in terms of storage.
  2. Using adjustment layers also offers you the ability to create a separate interpretation of the file—a black-and-white version, for instance—while still making use of some of the work done for other versions, such as retouching.
 
Define ‘Parametric Image Editing’ :-

In video editing, referenced file editing is again
necessary because file sizes are too large and processors are too slow to work with the full-
resolution assets.
We’re going to call the editing of images by creating instructions or parameters parametric image
editing (PIE). For the purposes of this paper, we’ll call the software that does this PIE software.
 

What is the difference between a Live Rendering and a Fixed Rendering ?
Nearly all digital cameras produce a mosaiced image as a raw file. Although this may look like a regular photo once it’s displayed in software, in reality it is a checkerboard of red, green, and blue values that are transformed into an RGB image when the file is processed by a Raw File
Converter. When we look at one of these raw photos on our computer screen, we either see a 
live rendering of the mosaiced data, or we see a fixed rendering in the form of a JPEG preview that has been made by the camera and placed inside the raw file.

List three advantages of NDI :-



  1. Multiple photo manipulation: Digital cameras have the ability to produce large numbers of similar files in a way that scanning photos never would have. Parametric image editing (PIE)the process of editing images by creating instructions or parameters for adjustment—makes it easy to apply settings made for one photo to many others very quickly.
  2. Unlimited undo: Since all image adjustments are saved simply as processing instructions, it’s easy to change those instructions to create a different interpretation of an image. In order to save the additional variations, all the user needs to do is to save the instructions that are used to create the variations.
  3. Space savings: Now that computers are fast enough to create renderings from the images as needed—let’s call this just-in-time rendering—the user can build a library of images that consists largely of the source images and the rendering instructions. Since instructions are a lot smaller than pixels to store, the storage requirements are greatly reduced.


Wednesday, 3 August 2011

Ex 4 - Colour Theory



Exercise 4 – Colour Theory 2

1.     Start Photoshop and open the document you created in Exercise 3.
·       What is the keyboard shortcut for opening an existing Document ?  command “O”   
2.     Change the Blending Mode of the layer Group to ‘Pass Through’.
3.     Make the background layer the working layer by selecting it in the Layers palette.
4.     Use the Rectangular Marquee tool to select the top half of the image.
5.     Use the Paint bucket tool to fill this area with Black.
·       What is the keyboard shortcut for this tool ?             command “B”    
6.     Change the Blending Mode of the ‘Red Circle’ layer to ‘Lighten’.
7.     Do the same for the Blue and Green Circle layers.
8.     Select the Move tool.
·       What is the keyboard shortcut for this tool ?             “V”      
9.     Turn on the ‘Auto-select’ option and set it to ‘Layer’ (Not ‘Group’).
10.  Drag the three circles so they all overlap each other.
11.  This simulates the     RGB                 Colour System.
12.  Rename the group of circle layers to indicate this.
13.  Add a text layer (using white text) saying ‘<name> Colour System’.
14.  Select the group of circles in the layers palette.
15.  Duplicate the group using ‘Layer -> Duplicate Group …’.
16.  Use the Move tool with ‘Auto-Select’ set to ‘Group’ to drag the new group to the bottom half of the page.
17.  Change the Blending Mode of the this group to ‘Difference’.
18.  This simulates the     CMYK               Colour System.
19.  Add a text layer saying ‘<name> Colour System’.
20.  Save the document as ‘Ex 4 – Primary_Colours.psd’


Ex 3 - Primary Colours


Exercise 3 – Colour Theory 1


1.     Start Photoshop and create a new document with the following properties :-
·       Name : ‘Ex 3 – Primary Colours’
·       Size : A4 @ 300dpi
·       Colour Mode : RGB / 8 bpc
·       Background Colour : White
2.     What is the keyboard shortcut for creating a new Document ?  Command “N”
3.     What is the size of the image in :-
§  Megapixels -            10.8        Megabytes  1.1
4.     Set the foreground colour to Red (ie R 255, G 0, B 0).
5.     Select the Ellipse Tool (not the Marquee tool). What is the keyboard shortcut :-    “M”      
6.     Draw a circle with the Ellipse tool approximately 6cm in diameter (about 1/3rd of the page width) – display the rulers and use Preferences to set the units to cm .
·       Which key forces the ellipse to be a circle ?           shift       
7.     Change the layer name to ‘Red Circle’.
8.     Duplicate the layer and
·       change the colour to green and
·       change the name to ‘Green Circle’.
         Note: To change the colour click on the colour button on the option bar immediately after duplicating the layer, or double click on the layer in the Layers palette.
9.     Duplicate this layer and
·       change the colour to blue and
·       change the name to ‘Blue Circle’.
10.  Select the Move tool. What is the keyboard shortcut ?   “V”        
11.  Turn on the ‘Auto-select’ option.
12.  Spread the three circles across the top of the page with a small space above them (they may overlap a bit – that’s OK).
13.  Fit the image to the screen (ie so the whole page is visible).
·       What is the keyboard shortcut for this ?       Command ”0”
14.  Go to Full Screen Mode – ‘View -> Screen Mode ->Full Screen Mode’.
·       What is the keyboard shortcut ?    "F"
15.  Stare at the centre of the middle circle for 20 seconds, then look at the white area below. You will see an after image.
·       What colour are the after images for each circle ?
Circle
After Image Colour
Red
blue
Green
yellow
Blue
red

16.  Select all three layers in the layers palette.
17.  Group the three layers together by selecting ‘Layer -> Group’.
·       What is the keyboard shortcut ?     command “G”
18.  Select the group in the layers palette containing the three circles.
19.  Change the ‘Blending Mode’ for the group from ‘Pass Through’ to ‘Difference’. (We will be looking at Blending Modes later, so don’t worry if you don’t understand them now).
20.  Stare at the centre of the middle circle for 20 seconds, then look at the white area below. You will see an after image.
·       What colour are the after images for each circle ?
Circle
After Image Colour
Cyan
magenta
Magenta
yellow
Yellow
cyan

21.  Save the document as ‘Ex 3 – Colour Theory.psd’
22.  What is the size of the .psd file on disk ?      more then twice the size      How does this compare to the image size you recorded in step 3 above.