Useful Photoshop Hints
Article by Peter B
Cropping
When cropping a section within a photo, the cropped area can be rotated clockwise and counter clockwise by positioning the mouse pointer outside of one of the crop corner anchor points.
Also a photo can be cropped to a specific size by filling in the width and height in the boxes to the right of the of the crop icon in the options bar. There is a clear field on the right to revert your crop to free form cropping.
To add canvas to your picture using the crop tool, press the letter d to set your default colour to white, press Ctl + - (minus sign), to automatically add a grey area around your photo, press f to clear the border around the image (f repeated turns it black then back to the border and normal screen), press c to call up the crop tool. Click the mouse pointer inside the photo on the screen and drag out a crop area that can be made larger than the photo. Double click or hit the return key and a white area is added around the photo, if required text can be added within the white border.
Tool Presets
If you frequently use a tool with specific options set this tool can be added to the tool preset window. Tool presets can be selected from the Window dropdown list, and the tool currently in the options bar can be added to the preset list by clicking the left icon at the bottom of the tool presets window. Unwanted tools can be dragged and dropped into the dustbin icon.
Levelling an image
Where a horizon is not level in a photo photoshop can be directed to calculate the exact angle for correction by using the Measure tool. The measure tool resides in the toolbox as one of the tools under the eyedropper colour selection tool, right click on the eyedropper and select measure. Where the horizon is slewed click once on the horizon, holding down the left mouse button drag out a straight line along or parallel with the horizon and click a second time.
Now go to Rotate Canvas, from the Image drop down list and select ‘Arbitary’, the exact angle has been filled in for you, you just need to hit OK. A crop will now need to take place as the entire image has been rotated. Clear from the options bar will remove the measure tool line.
If an image has to be rotated or moved about it helps to select Show > Grid from the View dropdown list. Now press Ctl+A to select the entire photo then Ctl+T to select Free Transform tool. Place the mouse pointer outside the photo, press the left mouse button and drag the entire photo clockwise or counter clockwise using the grid as a guide.
If an object within the photo needs to be re-positioned, nudge the entire photo right, left or up and down using the up/down, right/left keys on the keyboard. While Transform is active, the options bar provides seven fine tune selections that can be used as an alternative. Again a crop will have to take place (press C to switch on the tool).
Increasing the size of an image to poster size with little loss of resolution
Use the Image > Image Size option. Ensure Constrain Proportions and Resample Image is ticked. Use Percentage for Document and enter110% into Width, height will show 110.01. This will increase the image size by 10%, if this procedure is repeated a number of times in 10% increments the resolution is barely softened.
This repeated procedure can be a bit arduous if done manually, but it can be automated. Go under the Window menu and chose Actions. When the palette appears click the Create a New Action Button. Name it Upsize 110% and chose a Function Key to assign the action to, I suggest F11 or F12.
Now click the Record Button. Repeat the Image resize procedure again and all actions will be recorded, finally click on the square Stop button to stop the recording. Now every tome you use the selected function key the upsize process will be repeated automatically. You need to run the process 12 times to increase a 5” x 7” image to 18” x 24” or poster size and the loss is negligible.
Compensating for ‘Too Much Flash’
Ctl+J to add a new layer 1 to the background image, change the Layer 1 blend mode from Normal to Multiply this will remove some of the flash brightness, it it is not enough repeat the process Ctl+J and Multiply.
Dealing with ‘Digital Noise
Low light photos can be a bit grainy; this can be reduced by changing
Image > Mode from RGB to Lab Colour.
Now select Window > Channels, it now shows Lab, Lightness, a & b. for the image.
Deselect the eyes from all channels except ‘a’
Select the Gaussian Blur Filter, increase its radius pixels until you see the dots pretty much disappear then hit OK, (try radius 2)
Now only select the ‘b’ channel.
Ctl+F will repeat the same Gaussian blur to this channel.
Go back to Image > Mode > RGB colour and the bright digital noise spots will have been reduced.
Removing Colour Aliasing Noise. Chose Filter > Blur > Gaussian Blur .
Drag the Radius slider all the way to the left, and then drag it to the right until the colour aliasing is blurred enough so you cannot see it.
Go to the Edit menu and chose Fade Gaussian Blur
Change the fade mode to Colour and the colour aliasing will disappear.
Fixing under exposed photos
Use Ctl+J to create a duplicate Layer, on this layer change the Blend Mode of the layer from Normal to Screen, this will lighten the entire photo. Repeat this procedure until you are happy with the exposure of the photo.
Creating a Fill in Flash affect
Image > Adjustments > Levels
Initially drag the middle input slider (the grey one) until your subject looks properly exposed, you also may have to slide the highlights slider to the left to achieve a good exposure of the main subject, click OK. The background will now look blown out.
Go under the Window Menu and chose History. There should only be two entries called History States.
Click on the word ‘Open’ to select the open state, now click in the blank square to the left of Levels, a history brush type symbol will go in the square. Chose the History Brush tool from the tool box, use a soft-edged brush from the options bar. Now paint over the subject only carefully avoiding the background, this will bring back the original subject brightness and leave the original sensibly exposed background. This gives the appearance of a fin in flash to the subject.
Repairing Key-toning without using the Clone Tool
Key-toning affects tall building where they appear to fall away due to perspective.
Ctl+A (select all) CTL +T (Transform)
Drag the centre anchor points to meet the bottom anchors.
Drag out the top anchor points outside the picture to correct the perspective errors.
This may make buildings etc look a bit squat, so drag back up the centre anchor points until a more sensible image is achieved. When you are happy press Enter
The image my still look a bit bloated, this can be improved by using Distort and Pinch from the Filter menu. Click on OK to complete the correction.
Colour Correction
Before making colour corrections to your photos, set up Photoshop with optimum colour settings.
Select Shift+Ctl+K to bring up the Colour Setting screen.
Change RGB from sRGB IEC61966-2.1 to Adobe RGB (1988).
Open an image and select Image > Adjustment > Curves.
Double Click on the left hand eyedropper under the Options button (Shadows)
Change R G & B each to 20 click OK
Double click on the centre eyedropper. (Midtones)
Change R G & B each to 128 click OK
Double click on the right eyedropper. (Highlights)
Change R G & B each to 240 before you click OK, you will get an alert asking you to save the new target as default, click OK to this.
You can now select the curves or eyedroppers to make corrections to your image, either can be selected to the left of the recently adjusted eye droppers.
Exit the Curves screen with an OK, go to the Layers history and click once on the black and white disk this selects the adjustment layer options. Select Threshold, second from the bottom of the list, this turns the image black and white and opens the threshold screen.
Drag the threshold slider all the way to the left the photo turns white. Slide this slider gently to the right, the first black that appears is the darkest part of your photo, click ok to close the dialog. This adds threshold 1 to the layers palette. Select the Colour Sample tool, eye dropper from the tools box. Click the dropper once onto the darkest area shown, a sample area and 1 will appear as does the info palette, ignore or close this.
Now to find the white threshold area, go back to the layers1 threshold screen and double click on the black and white circle, on the threshold screen drag the slider all the way to the right then gently back to the left until white starts to appear on the black screen click OK in the threshold dialog. Again use the colour sampler tool and click one on the white area to select the highlight area, a 2 appears on the selected point.
The threshold layer can now be discarded by dragging it onto the waste bin. The photo now looks normal with the selection points 1 & 2 showing.
Now type Ctl+M to bring up the Curves dialog, first select the shadows eyedropper, the half filled black one, move the cursor dropper to target 1 on your photo and click once, shadows are set, your photo should lighten slightly.
Now select the Highlights dropper from the curves dialog, (the right hand all white dropper), select target 2 with the dropper and click once. Highlights are set.
Now chose the Mid Tone dropper, this is not so easy to select. This can have a dramatic effect. Select the curves Mid Tone dropper, go to the Info palette and by default the top left panel shows RGB colour values. Hold the mid tone eye dropper over the dropper symbol in this panel and left click once, from the drop down list chose Total Ink.
Now move the eye dropper over the photo and see if you can find a total ink reading of 128, left click once when you get closest to this number. The two target areas can be cleared by clicking on clear in the options bar. Finally click switch the curves dialog to curves and adjust the centre of the curve up or down until the image is visually pleasing and click OK to close the Curves tool.
This will have corrected highlights, shadows, mid tones, colour cast and adjusted the overall contract and brightness of the image.
Colour correcting multiple images
Multiple photos can be opened at once in photoshop by using the standard Windows selection procedure, i.e. hold down Ctl. key to select multiple photos randomly, hold down the Shift key to select a sequential group of photos.
Select the first photo in the group, select an Adjustment Layer either by clicking on the black/white circle below the Layers palette and selecting Curves, levels, colour balance etc. or from Layers > New Adjustment Layer.
To apply the same adjustment to each photo, position each photo so an area of each is visible, i.e. tiered one over the other, ensure Window > History has been selected.
Place the mouse pointer over the adjustment layer 1 in History ( i,e. Colour Balance 1 Layer), left click it and drag the layer that has turned orange to the next photo, the same adjustment will be applied to this photo automatically. You can do this for each photo in turn.
Getting a better Auto Color. Correction
If you do not have time to use Curves or Levels to correct a photo select
Image > Adjustment > Auto Colour.
This does a reasonable correction but sometimes it needs to be tweaked as the affect can be too extreme.
One way to reduce this is Edit > Fade Auto Colour. (Only available immediately after applying Auto Colour). The Opacity slider reduces the affect. The Blend mode options also work here, multiply darkens, Screen lightens etc. Click OK.
Also press Ctl.+L for the Levels dialog, On the right side is the Options button. This is where the Auto Colour options can be found.
At the top select ‘Find Dark & Light Colours’ and tick ‘Snap Neutral Midtones’ This links the Auto button in Curves and Levels with Auto Colour selection under Image > Adjustment. If you click on the Shadow, Midtone & Highlights boxes you will see the default settings 20, 128 & 240 as set earlier. To save these settings tick the Save As Default box.
Colour correcting areas in an Image.
Changing the colour balance in a photo is achieved using the following:-
Layers > New Adjustment Layer > Colour Balance, or under the black/white circle on the Layers Palette. This affects the entire photo.
Press the ‘d’ key to set the foreground colour to Black. If this does not work, click on the curved two pointed arrows above the Foreground/ Background symbol in the Tool Box, until Black is on top. Now select a large soft brush from the Tool Box. Paint over the image to remove the applied Colour Balance changes from areas within the image leaving the Colour Balance change where you want it.
Changing the brush size and edges to hard allow a more precise removal of colour balance.
To adjust the brightness of Colour Balance, go to the Colour Balance Layer in the Layers palette, hold down the Ctl. Key and click on the word Colour Balance in the palette, the colour Balance area in the image will now be selected and can now be adjusted using Layer > New Layer Adjustment tools. Also the transition between
Colour Balance and the erased area can be smoothed using Select > Feather.
Finally go to Layers > New Adjustment Layer > Levels and click OK. To cancel the selected area.
Extracting objects from an image.
The quickest way to extract an object from a photo is by using the Filter > Extract tool. This brings up the extract screen, chose the edge highlighter (looks like a felt tipped marker), select a fairly large brush size, its size can be increased or decreased by pressing the square bracket keys.
Trace around the desired object overlapping it 50/50 with the background, select the fill tool, (one down from the edge highlighter), and click the tool once within the area selected, it turns a mauve / blue colour. You can now select the preview button, check if fine details like some ones hair has been selected, if you are reasonably happy with the preview press OK.
There may be a few dropout problems, hit Ctl.+J to duplicate the layer, this sorts out most of them, hit Ctl.+E to merge the layers and correct the rest by enlarging, and alternating between the History Brush and the eraser brush.
Having made your selection you may wish to paste it into another image, open this image, drag the background onto the extracted image, you can then return to the extraction and repair dropouts with the history brush.
Finally go to the Layers palette and drag the background layer behind the extracted layer to bring it on top. Clean up any unwanted junk with the eraser tool, flatten the layers.
An Improved Dodging and Burning
Open an image to work on, go to the Layers palette and click on the little right facing triangle below the close cross, this will bring up a drop down list, select New Layer a dialogue box opens, change its Mode to overlay and tick ‘Fill with overlay-neutral colour (50% gray)’. Select the brush tool with a large soft edged brush, Opacity 30%, press d then x to set foreground colour to white.
Paint over the areas on the image you want to lighten (dodge). The low Opacity allows you to build up the dodge gently and can be adjusted.
If there is an area you want to darken, press d to change the foreground colour to black and paint over the areas you want to darken (Burn).
An alternative method is open the image, on the Layers palette select New Layer (symbol to the right of the black/white circle), change the blending option from Normal to Soft Light. Again use large soft edged brush opacity 30%. To Dodge change the foreground colour to white, to burn change it to black. This technique using Soft Light is less aggressive as with the previous procedure. This procedure is easier to implement.
Blurred Lighting Vignette
This technique creates a glow immediately behind a portrait with a dark background emphasising the subject.
Open the image and select the Elliptical Marquee from the tool box. Drag an oval selection around the subject the size you want to be highlighted. Create a new Layer in the Layers palette, Hold down the Alt. key and click on the Layers Mask Icon at the bottom of the Layers Palette, (the square with a circle in the middle).
Now in the Layers Palette click once on the regular layers thumbnail, press ‘d’ to set the foreground colour to black, then press Alt.+ backspace to fill the layer with black but leaving a light oval window around the subject. Lower the Opacity to about 50% so the black becomes see through.
In the Layers Palette click once on the Layers Mask Icon, go to Filter > Blur > Gaussian Blur, in its dialogue box drag the slider all the way left then slowly right until the sharp border between the darker image background and the oval becomes diffused and blends between the dark surround and light subject.
Using Colour for Emphasis
This shows you how to highlight part of a black and white image with colour.
Select a large hard edged brush from the Tool Box, change the blend mode to colour in the options bar. Ensure the foreground colour is black, paint in the image where you want colour to be removed only leave the item to be emphasised. If you make a mistake while removing the colour change to the History Brush and paint it back in.
Adding Motion where you want it
If you have photographed an athlete with a fast shutter speed the image will have very little signs of movement in the figure, to add motion blur, duplicate the background image, from Filter > Blur select Motion Blur. Its dialogue box presents Angle showing the direction the blur comes from and Distance determining the length of blur. Set the angle to 4 degrees, almost horizontal and move the distance slider (Amount) until you are happy with the extent of the blur. Hold down the Alt. key and click on the Layer Mask Icon at the base of the Layers Palette, this hides the blur. Get the brush tool from the tool box, soft edge medium sized brush, press letter ‘x’ to change the foreground colour white. Paint over the area where you want to see motion blur, if you make a mistake change the foreground colour to black and correct it.
Replacing the Sky
Open the image where the sky needs to be replaced, use the Magic Wand tool with careful adjustment of Tolerance to select the sky, this is better if the sky is fairly uniform in colour.
Press the Alt. key and the Lasso tool to de-select areas where the magic wand should not have selected. Take a photograph of some sky that you would like to use as a replacement, open this image and got to Select > All, use Ctl+C to copy the sky photo into memory.
Go back to the original image with the selection in place, go to Edit > Paste Into, the sky will be pasted into the selected area. You can change the opacity setting in the Options bar to blend the sky in better.
Using the Lightness Channel to convert to Greyscale
Open the image, under Image > Mode > Lab Colour.
Go to the Channels Palette, de-select every channel except Lightness, the image is now greyscale.
Go back to Image > Mode > Greyscale, hit OK to dicard the other channels. The channels palette now only shows gray.
Go to the Layers Palette click on the background layer, Ctl.+J to duplicate it.
Switch the Blend Mode of this duplicate layer to Multiply to darken the image, now lower the Opacity of this layer to the ideal tonal balance. This method gives you more control than by selecting Greyscale from the Mode menu.
Custom Greyscale using Channel Mixer
Open an image, chose Channel Mixer from the Layers Palette Adjustment popup, this opens it in a new layer for ease of editing. Tick the Monochrome box at the bottom left of its dialogue box.
The image turns Greyscale and the original colour sliders can be changed to achieve the desired greyscale image but the total percentage settings must equal 100%, Constant allows you to change the over all luminance of the image. Click OK to apply the changes.
If you want to further edit the image, go to the layers palette and double click on the layers adjustment icon within the channel mixer layer. Dragging this layer into the dustbin will revert the image back to colour again. To achieve a greyscale image with real contrast and depth, drag Red to +160%, Green to +140% and Blue to -200%, tweak the Constant to your liking.
Different Sharpening methods
Basic method:-
Filters > Sharpen > Unsharpen Mask.
Sharpening soft subjects - Amount = 150%, Radius = 1, Threshold = 10
Maximum sharpening - Amount = 65%, Radius = 4, Threshold = 1
All purpose sharpening - Amount = 85%, Radius = 1, Threshold = 4
(Dropping resolution from 300ppi to 72 for the web can make it grainy. Use these settings to compensate).
Web sharpening - Amount = 400%, Radius = 0.3, Threshold = 0
This is a guide, do tweak the settings yourself.
Colour Lab Sharpening:-
Image > Mode > Lab Colour
Under Channels Palette, click on the Lightness Channel
Filter > Sharpen > Unsharpen Mask
Use the basic method settings.
Change the Mode back to RGB for results,
Luminosity Sharpening:-
Filter > Sharpen > Unsharpen Mask
Apply basic settings
Edit > Fade Unsharpen Mask, in its dialogue box change Mode to Luminosity. OK
You can now apply a higher amount of sharpening without halos.