CONVERTING AND EDITING RAW

IMAGES

RAW V JPEG

• As we have

found out, jpeg

files are

processed in the

camera and

much of the

data is lost.

• Raw files are

not and so all of

the data is

preserved.

RAW FILE FORMATS:

• General term for a variety of proprietary file formats

– Canon .CRW and .CR2

– Nikon .NEF

– Minolta .MRW

– Olympus .ORF

– Sony .SRF

PROCESSING RAW DATA

• Unprocessed raw data can be converted into usable

file format using Adobe Camera Raw (ACR).

• Settings such as bit depth, white balance, exposure,

brightness, contrast, saturation, sharpness, noise

reduction and crop can be applied during the

conversion process.

• Making changes using the full bit depth image (raw

file) enables us to achieve better results.

• Simply double-click the file to open it into Photoshop’s

Adobe Camera Raw editing suite.

PROCESSING RAW DATA

• The dialogue we are now working with has been organised so that the user starts with the top slider then works their way down to the bottom.

• You can also process a number of images at once, for example if they are of the same subject, using the same setting at the same time on each image.

• Processing steps:

– Step 1 Straighten , crop and size

– Step 2 Colour space

– Step 3 Choosing bit depth

– Step 4 White balance

– Step 5 Tonal adjustments

– Step 6 Saturation and vibrance

– Step 7 Noise reduction and sharpening

BASIC TOOLS:

Basic Tools

File Options

File Histograms

Adjustment Panels

STEP 1: STRAIGHTEN, CROP, SIZE

• Straighten the image with the straighten tool or by rotating a crop area.

• Crop the image with the crop tool.

• Size the image with the crop tool option menu.

• Set the resolution using the Workflow options at the bottom of the screen.

STEP 2: COLOUR SPACE

• The colour space is the level of colour you have to process

within in your image:

• Colour Match RGB - is rarely used now.

• sRGB – This offers the smallest range of colours so should

be chosen for images which will be used on screen e.g. web.

• Adobe RGB (1998) – The most common colour space used

in industry for print images.

• ProPhoto RGB - should to be used if you have access to

high end printing equipment – must work in 16bit to avoid

data loss.

STEP 3: BIT DEPTH

• Bit depth = the amount of information you have to

process, the higher the bit depth, the more

information you have to work on, thus a better

resulting image.

• Working in 16 bits per channel will preserve all the

information in the image.

• On opening the image into the standard Photoshop

workspace, as long as no editing takes place the image

will stay 16bits per channel.

• If editing takes place then 8 bits per channel will be

used, compromising quality.

8 BIT V 16 BIT EDITING

• In 8 bit editing the channels are weaker and begin to break up.

Not so with 16 bit.

8 bits per channel

256 tones per channel

16 bits per channel

32,769 tones per channel

• The difference is that the 8 bit edit may result in banding instead

of smooth gradients from one colour/tone to another.

STEP 4: WHITE BALANCE

• White Balance option allows choice

of presets including As Shot

• Temperature slider controls

blue/yellow

• Tint slider controls green/magenta

• Both together control red/cyan

balance

• Alternatively use the White

Balance tool to select a mid grey in

the image to auto balance it

STEP 5: TONAL ADJUSTMENTS

• Exposure slider sets the brightest points in the image

• Blacks slider sets the darkest points in the image

• Brightness and Contrast can be used to fine tune the midtone values

• The Recovery slider is used to rescue highlight tone that might clip as they are adjusted.

• Fill Light will rescue very dark tones that may contain texture or detail

Just like Levels in Photoshop

Click Auto to auto

balance or Default to

reset

CAREFUL

• Tall peaks on the histogram indicate that you will lose shadow highlight or colour detail when you export to Photoshop.

USING THE TONE CURVE

• Editing the tone curve gives you the same flexibility as Curves in the normal Photoshop space.

• Lifting the line from the centre will generally lighten and dropping it will generally darken

• To lighten the light areas and darken the dark areas, add three points down the line and lift the top and drop the bottom points.

• You can add as many points as you require.

• You can select points from the image by holding down Cmd and clicking on the image.

STEP 6: SATURATION &

VIBRANCE

• These two commands allow for the

increase or reduction of colour

within the image.

• If the image already has a high

concentration of colour then it is

easy to clip the image.

• Clipping means to lose some of the

high end colours and should be

avoided.

• Again watch the histogram for

spikes at the left and right.

EDITING THE INDEPENDENT

COLOUR CHANNELS

• The HSL/Greyscale tab can be used to edit the individual colour channels for far more control over the process.

– Hue: controls the colour

– Saturation: controls the amount of colour

– Luminance: controls the light and dark in each colour

• The Greyscale selection converts to greyscale allowing the same control sliders to control the greys in each channel. This histogram will show a single grey channel.

STEP 7: NOISE REDUCTION AND

SHARPENING

• Zoom in to 200% and inspect the image for noise

• Noise can be reduced using the Luminance and Colour sliders

• You should only use these if noise is present as fine detail can be lost.

• Sharpen the image using the Amount slider

• Care should be taken her also, don’t sharpen above 25% as it will have no effect in the actual final file editied in Photoshop.

SENSOR DUST, SPOT & BLEMISH

REMOVAL

• Click the Retouch tool, select a radius, click on the problem – Photoshop auto selects an area to use to heal with. The green circle an be moved to select a better area if required. Clear all will reset the image.

RESETTING THE RAW IMAGE

• To reset to the original raw

image as it was when it game

off the camera do the following:

• Click the menu at the top of the

adjustments areas and select

Camera raw defaults.

• To remove any crops you have

applied, click and hold the crop

tool then select Clear Crop.