Posted on April 25, 2016
Resizing images is something you will always need to do as a photographer, so knowing how to do this precisely and for a range of reasons is something you will need to know.
Basic Pixel Resolution Sizing. The method you will be most used to using is Image/Image Size.
With width and height locked you would merely type in the resolution you require. If a client asks for an image no more than 2500 pixels on the longest side, with the width and height locked, you would merely type this in the Width section and the Height will be adjusted accordingly to keep the image aspect ratio the same.
With Width and Height unlocked then only entering one value will change the image shape, so always use it locked unless you have a specific need. One thing often overlooked when resizing are the resampling options. Depending upon whether you are increasing, or decreasing an image in size, these should be selected carefully.
Reduced to 1500 pixels across with Bilinear
Reduced to 1500 pixels across with Bicubic Sharper (Reduction)
When reducing, as you can see, using Bicubic Sharper adds a little sharpening to make the image appear sharper on screen.
Increased to 15000 pixels across using Bilinear .
Using Preserve Details keeps the image sharper when increasing the image size. When using Preserve Details, if the image is noisy, you can add noise reduction at this stage, but my advice is to do so sparingly or detail can be lost.
Resizing for printing.
When resizing for printing, it is important to also set the print resolution. Most commercial printers, assume you are using a file of 300 ppi (Pixels per inch). The files off your camera however may not be set to this. Many cameras (including the camera this test image was taken with) set 240ppi.
Using image/Image Size you can also resize the print resolution. More often than not though, you will want to size an image for a specific print size. For example, if we wanted to size this test image to print at A2, we’d need to set the actual print size at 300ppi and also set the print size to A2. You need to know the actual print size, and this can easily be found on the internet. A2 is 59.4 x 42cm Before you size, take note of the original pixel resolution, and set the width and height to Centimeters Then type in the dimensions you need.
Bear in mind, that almost certainly, the image will NOT be the same shape as an A2 page, so if it is a landscape image, set the width to 59.4. If a portrait image, set height to 59.4cm. THEN take note of how the pixel resolution changes…
As we can see the resolution has reduced, so we then need to choose the appropriate Resample method .
In this case, Bicubic Sharper, as we’re reducing pixel resolution. Our image is now 300ppi and will print exactly 59.4cm across. Resizing with the Crop Tool.
You can perform the same tasks with the crop tool.
Select the crop tool from the main toolbar.
Then on the context menu, select “W x H x Resolution”.
If you do not want to change the image shape, set width size only for a landscape image, and height only for a portrait image. And set 300ppi Bear in mind you have to actually type in the letters cm if you want centimeters.
You would then drag the cropping tool across the entire image (having snap turned on from the “view” menu helps here). Once the whole image is selected… double click to action the crop the image to the size and resolution set.
If you want your image to be exactly the same shape as the paper.. in this case A2 (59.4x 42cm) the crop tool is the ideal way to do it. Just set the exact paper size and 300ppi resolution.
As the image will not be the same size, you will need to decide how to crop it. Action the crop, and you will now have an image that will print exactly to A2. The problem with this method is that you cannot choose the resampling method. To get around this, you can crop to the required aspect ration first by setting the crop tool to “ratio”, and typing in the measurements you want… so for A2, you could type 5.94 x 42. No need to put cm etc, as it is a ratio. Crop… THEN use the Image/Image Size method. Then you can choose the resampling method.
Posted on November 17, 2015
Glitch art is the aesthetisization of digital or analogue errors , of either artefacts or other bugs by either corruption or manipulation .
1 Open the image you are using .
2 Duplicate the image then darken and mask off the background using the quick selection tool .
3 Next use the marquee tool to create long thin rectangular shapes over the image where you want the glitching effect to be as below .
4 Next select filter /distort/wave and type 2 for the amount of generators with min 20 and max 30 for both wavelength and amplitude . Also use filter/distort/pixelate/fragment as below .
5 Continue with this method until you are satisfied you have enough glutting for your required affect .
6 Repeat this process twice and use free transform to move the image slightly left right up or down to enhance the glitching effect .
7 Make a 50% grey layer and choose filter/filter gallery/halftone pattern with line pattern , 1 size and 50 contrast then choose the subtract effect . now darken that layer with control L/levels to your liking .
8 Use filter distory shear to bend the image to your liking . Also add any effects or layers as you require to achieve your desired effect as my image below .
Posted on March 1, 2015
Using a mixture of all 16 weeks previous digital imaging skills learnt we had to recreate one of the photo tasks given in our lesson . I chose the one below .
This my My Re-creation of the image using photoshop skills .
Posted on March 1, 2015
While some fashion and advertising images are heavily retouched, the best way to practice the techniques are to learn how to retouch naturally, with your aim to make the retouching undetectable unless compared to the original RAW image.
There is blotchiness and redness in the skin, there are spots, and there are areas of shininess/oily skin and also, being an available light photograph, some areas are high in contrast and result in deep shadows that are emphasising wrinkles and folds. While there is no one way to retouch, the main tools used are generally Clone Stamp, Heal, and Spot Heal. We will be using a combination of these three to remove the spots and stray hairs etc. As usual, we’ll make a copy of the background layer by pressing CMD+J or by dragging the layer to the new layer icon Once copied, rename the layers as original and Working Copy, or names that at least make sense to you. Next step is to create a layer purely to contain the retouching we will be doing. Click the New Layer icon, or use Shift+CMD+N You will now have a blank layer to retouch on. Call this layer Retouch. Whichever retouch tool you are using, check at the top of the screen in the context menu that you have set “Current & Below” set. This will ensure that nothing above the retouch layer is included in the sampling. It is important that you do the retouching first before the next steps, and that the retouching layer is directly above the image layer, as “spot healing” tool only has a context option for “Sample all layer” and this will include the other layers we will be creating shortly. As these layers effect colour, it’s very important retouching is done first. If possible, avoid using “spot healing” tool. If you DO need to go back in and retouch again, you can only use retouching tools that have “current & below” as in the context menu. Go ahead and retouch using whichever method you want, but make sure that you have the retouch layer selected, and “Current & Below” set in the context menu for sampling. When using the Heal tool, be careful not to go near edges of differing colours or contrasts, or the colour may be “pulled” out of the area like below. When going close to edges, use the Clone Stamp tool instead, or make sure the heal tool is aligned (as demonstrated in session) All your retouching should now be on one layer. Before and after. That’s all the retouching done, and it’s all on one layer. There are still issues with the skin however. There is redness, blotchiness, and lines/wrinkles. For natural looking retouching, these should not be removed using the retouching tools, as it makes the skin look too perfect. It may be ideal for a highly stylised fashion shoot, but the purpose of this exercise is to create utterly believable retouching. First we will deal with the redness of the skin, and coloured blotchiness left be spot removal. Step 2: Removing Redness and colour blotching. First of all, select what looks like a healthy skin tone from the image, using the Eyedropper tool from the main toolbar, and make sure this is the selected foreground colour. Create a new Solid Colour Fill layer by clicking the “Create new fill or adjustment layer” icon. And select Solid Colour. This will create a solid colour layer the same colour as the skin. It will completely hide the underlying portrait. Change its name to Skin Redness. Change the blending mode to “color” and you should have a monochrome image the same colour as the skin tone you selected. However, only want this colour to affect the skin tones. As the Solid Color layer is an adjustment layer, you will notice it has its own layer mask already added. If we invert this, by selecting the layer mask and pressing CMD+I it will invert the layer mask to black and restore the colour. Ensure your foreground colour is white (it should automatically do this when selecting the layer mask) and you can paint the new skin colour from the Solid Color layer back in with a paintbrush. Only paint in the skin. Do not paint on eyes, hair, clothes or lips. Only flesh. If the colour appears wrong, as shown here… Double click the Solid Colour in the layer itself, and a new colour picker will appear. Click on another part of the face until a healthy skin colour is found. Click back onto the layer mask, ensure white is the foreground colour, and carry on revealing the colour through the layer mask. Once completed, you should have an image that appears to have only one skin tone colour present. This obviously looks strange, but you’ll notice the redness is no longer present. Note how I have avoided the eyes, lips, hair, and clothes when revealing the Solid Color layer with the layer mask. To restore a more natural looking skin, we can now fade back the Solid Color adjustment layer by reducing opacity to around 50%. Already this is a massive improvement from where we started. Step 3: Dodging and burning. We’ve discussed dodging and burning on a layer in previous sessions, and we used a grey layer set to overlay to influence the underlying image. Previously we’ve used overlay to make quite dramatic changes to the image, which works well with very punchy, contrast images, or images with very hard lighting. However, the disadvantage with using a grey layer with Overlay as the blend mode, is that while it’s great to add dramatic effects, a portrait like this, where looking natural is required, Soft Light can be a more effective layer blend to use. Last session, we also recapped how to create mid grey by using R:128, G:128 and B:128. There is a quick way to do this, but I wanted you to understand what mid grey was. Now you do, feel free to use this quicker method. Click “Create a new layer” icon. Then go to Edit/Fill Then select “50% Grey” from the “Use” menu. You will now have a grey layer at the top of the stack. Rename it “Dodge & Burn” Set the layer blend to “Soft Light” and use the Dodge and Burn tools to lighten and darken areas that appear heavy, or light accordingly. Please remember to alter the size, and hardness of your brush. Ideally a graphics tablet should be used here, but it is perfectly possible to achieve god results with a mouse, providing size and hardness is used appropriately. Wrinkles and folds can be reduced using this method, but you must zoom right in, and use very small brushes. Here is my Dodge & Burn layer.(next page) Notice how I have used a big, soft brush to adjust large softer areas, and then used very hard, small brushes to adjust wrinkles and small details. Here’s a zoomed in look at the lines around the mouth and nose. The results of this can be seen below. The overall effect is shown on the next page. Finally, check for colour balance and colour casts with a Levels adjustment layer.
Posted on March 1, 2015
Converting a colour image to black and white .
If we simply remove colour, or shoot the scene with black and white film, or even set the camera to black and white, the problem is we have no control over where the tones will lie in relation to one another.
As you can see, once we simply remove colour, different colours appear similar .
This is not a problem with digital cameras. If we had shot the scene with black and white film, the same problem would have occurred. The reason is that we see the world not only with colours, but with varying brightness levels too. While being different colours, the cars are roughly the same brightness, so once colour is removed they all appear the same shade of grey. If you were shooting black and white film, you would use colour filters over the lens. For instance, a red filter would pass red light with almost no loss in brightness, but would block blue light quite severely, so the results would be the blue car being very dark and the red balls being very light. This is how photographers such as Ansel Adams got the rich, dark skies and bright white clouds.
The colour you want to darken is the opposite of the colour filter you should choose.
The same problems persist in digital photography however, as the first two images show. The solution lies in filtration, just as it did with black and white film, but this can obviously now be done digitally with the RAW file.
We open the RAW file in Adobe Camera RAW (the same controls are available in Lightroom or Capture One) and click on the “HSL/Greyscale” tab and check the “convert to greyscale” box.
In order to adjust the tones, we would adjust the colour channel sliders appropriately as per the colour wheel on page2. The only difference is that when adjusting digitally, we actually adjust the colour we want to change directly.
With film, if you wanted to darken blue, you would add a red filter. Digitally, if you want to darken blue, you lower the blue channel slider. It helps if you have a colour version to hand by which to judge this. As the red car appears brighter in colour (its not, its just a more vivid colour) we will lighten the red car by adjusting the red, purple and magenta channels (they’re a pinky/purplish red). We want to darken the blue car too; as blue is perceived to be the darkest colour, we’ll reduce this. We also need to darken the green grass, but its actually greener than blue, so the aqua channel was reduced as well as the green. This resulted in a greater separation of tones .
Create a black and white adjustment layer (see previous page). This will turn the image black and white, and give us the channel adjustment sliders. If we select “Luminosity” as the layer blend, colour is restored.
However, when we now adjust the channel sliders, we can see the levels for each channel being adjusted in colour. We can paint the areas of the B&W adjustment layer’s layer mask in black, by selecting the layer mask icon ,you can even add a saturation adjustment layer, and increase saturation on the green and yellow channels. These effects are subtle, but the difference can make it worthwhile.
Posted on February 9, 2015
“The sensitivity range of the human eye is enormous. From full sunlight to starlight represents an illuminance range of more than 10 million to 1.” Graham Saxby, The Science of Imaging, IoP Publishing, 2002, p30.
In effect, what this is saying is that our eyes see The whole dynamic range …but our camera only is one or the other
This is because the dynamic range of even modern digital cameras is around 12 stops, whereas our eyes and our brains can cope with exponentially more than this. Most amateurs or hobbyists however assume that an HDR image looks like what you typically see on amateur urban or urban exploration sites . That is not an HDR image. It’s a tone-mapped image from an HDR source. It’s also a badly tone-mapped image, and is fast becoming a cliché. It also destroys the quality of the image by adding artefacts such as halos around contrast boundaries, and high levels of noise. The purpose of a HDR image is to map the wide range of tones into something that is believable as a normal image. In order to do this, a series of RAW files are produced over a wide range of exposure values, from very under exposed to reveal fine highlight detail, to very under exposed to reveal fine shadow detail. The images are then loaded into software to create a very high bit-depth, wide dynamic range file. The dynamic range of this file cannot be seen on the screen, nor can it be printed, as no print process or screen exists that can display such a high contrast range. The purpose of the file is merely contain all the detail, which is then remapped into a visible dynamic range to be seen or printed. There are many pieces of software that can do this. Photomatix is popular, but is mainly used to create HDR special effects as seen above. One of the best tools for creating realistic HDR images is already part of Photoshop: “Merge to HDR Pro.” In order to use it, you must have a series of suitable RAW files ranging from at least 2 stops under, to 2 stops over exposed, and preferably in 1 stop increments, so at least 5 images is normal. Less can be used, but less than 4 or 5 begin to degrade the process. The more files, and the wider the range of exposures captured the better the results. As several files of differing exposures are needed, the subject matter dictates what’s possible or not. Scenes with lots of movement do not work well, as there will be significant differences between frames. Landscapes, interiors and still life are usual subjects. Tripod use is essential.
Step 1: Creating the 32bit HDR file. Place your range of RAW files in a folder, then in Photoshop, go to File/Automate/Merge to HDR Pro. A dialogue box will appear. You can navigate to a folder, or to files. If Folder is selected, then all files within that folder will be loaded into Merge to HDR Pro. If Files is selected, then you open the folder and manually select the files to load. Once selected the files will be displayed.
Ticking “Attempt to Automatically Align Source Files” will align files in case there was any movement between frames. Click OK. The RAW files will load into the software, and the Merge HDR Pro window will open and display your image. Step 2: Creating the Tone-mapped image With Photoshop CC, we now have the option of converting the images into a single Smart Object and actually use the raw files directly within Adobe Camera Raw. This means that it’s not only a 32bit image, but can be re-edited at any time, and no permanent changes are being made. 32bit images are not directly useable, as their dynamic range is too wide for monitors, printers etc, but first creating a 32bit Smart Object file and saving it gives you a “digital negative” that contains the exposure width of ALL combined raw files. In order for the smart object to continue working, your files can not be moved from their original location, so this is another reason to have a sensible file and folder strategy . Once Merge to HDR has loaded all your files into layers, you have a new option in Photoshop CC for 32bit working, and that is “complete toning in Adobe Camera Raw” Ensure this is ticked, and it may be worth also ticking “remove ghosts” as this helps remove items from individual raw frames that are not present in all, such as a bird flying past in one frame only.
Then click “Tone in ACR” The raw files will be ALL opened in ACR as a Smart Object. At this point, Just click OK without adjusting anything. You’ll see that once the image is now open in Photoshop, it’s layer palette icon has changed, and there are new adjustment layers. These are indicating that the image has been converted into a Smart Object, and there are Smart Filters applied. If you save the image now using File/Save As, as a PSD (photoshop file) you will have a 32bit digital negative that will allow a huge range of adjustment with much less loss of quality than any other method. Once you have saved this smart object 32bit file, the raw files it links to cannot be moved or it will break the link. Make sure you put your raw files in a place you are happy to leave them (see session 1). The beauty of smart objects and smart filters is that you can go back in and make adjustments at any time, and no permanent changes are being made to either the linked raw files, or the actual smart object itself. Double clicking on the “Camera Raw Filter” layer will re-open ACR and let you carry on editing. Initially, lowering “highlights” and increasing “shadows” in ACR will demonstrate how much more dynamic range has increased by combining all 5 raw files into a smart filter. this may look a little flat however, so you can make adjustments to suit your needs, but to take advantage of the HDR file, high shadow settings, and low highlight settings are generally desirable. If the image looks flat, you can make adjustments to ‘blacks’, and also make curve adjustments. You have to remember at this point, that we are still working at 32bit level, and this file is not useable at this point. It can’t be accurately printed, nor even viewed, as printers and monitors cannot handle 32bits of colour depth and dynamic range. Once we have the image roughly adjusted as we want, we can now convert it to 16bit, and this is where CC’s Smart Filters come into their own, as even after converting to 16bit to be viewed and edited, it still links to the original raw files, and is still fully reversible. Select ‘Image/Mode/16bit’ (next page) You will initially be greeted with this warning You may ignore this – it’s a general warning, and not specific to this exercise. However… the NECT warning should NOT be ignored. If you merge layers, it will convert the smart object back to a normal layer, and your ability to adjust the image by using ACR will be lost. SELECT “Don’t Merge”. Your image will now be 16bit, and the HDR 32bit tones are being remapped and compressed into a 16bit space. You can always check what bit-depth you are working on by looking at the file name in the image tab. This is now a 1bit file. As the tonal range has been compressed, the image will look flatter at this stage, but don’t worry, as double clicking the ‘Camera Raw Filter’ smart filter layer will re-open ACR and allow you to continue editing the 32bit HDR set of raw files, but will now accurately convert them to 16bit. As we are essentially working on raw files (via the smart filter) we can also make some quality adjustments other HDR methods do not allow, such as removing chromatic aberration or applying sharpening/noise reduction. The biggest advantage of this method of HDR management is that this is not only reversible, but does not add the artefacts other methods to, such as hallows, fringing, noise etc. HDR images created by this method just look like normal, full tonal range images, nut with great shadow and highlight detail. Just to demonstrate the power and advantages of using CC’s new ACR Smart Filter method of mapping HDR images, I’ll try to recreate this using only the 1 “correct” exposure raw file. (see next page) Proper HDR conversion Recovered shadow detail from a single raw file. At any time, you can save this file using ‘File/Save As’ as a PSD file, and carry on re-editing it using the Smart Filter in ACR so long as the raw files have not been moved.
Once you are completely finished and happy, you can if you want flatten the image to archive as a TIFF file.
Posted on December 6, 2014
|allentimphotos2 on The Man Bar|
|Stephen shaw on The Man Bar|
|allentimphotos2 on The Man Bar|
|Stephen shaw on Colin|
|allentimphotos2 on Colin|