Photoshop. Photoshop: its history and its compositing toolset. Martin Constable April 29, RMIT Vietnam

Transcription

1 Photoshop Photoshop: its history and its compositing toolset Martin Constable April 29, 2017 RMIT Vietnam

2 Introduction Introduction Some History The Compositor s Workspace Key Compositing Skills 1

3 Some apps are very focused in their application. Photoshop aims to serve a whole range of creative communities: web designers, matter painters, photographers etc. In this lecture, we will concentrate on only one of Photoshop s skill-sets: compositing. Compositing is another term for Photoshopping 1... i.e. mashing two or more images together to make a new image. 1 Photoshop is the only app to have become a verb! 2

4 Some History Introduction Some History Thomas Knoll John Knoll Adobe Photoshop 1 Layers The Compositor s Workspace Key Compositing Skills 3

5 First... some history! 4

6 Thomas Knoll Photoshop (PS) was invented by Thomas Knoll. He started work on it in the 1980 s when he should have been studying for his PhD (which he never finished). 5

7 The first version (called Display ) did no more than open an image, offer the ability to perform a gamma adjustment, and save the image. 6

8 John Knoll This is Thomas s brother John. 7

9 This is also him, as the overweight pilot of a starfigher in Star Wars, The Phantom Menace. He was a visual effects artist at LucasFilm. Together, they tried licensing PS to companies, including Lucasfilm and Apple. All turned it down. 8

10 Adobe Eventually, Adobe licensed it. They were a boring company who were famous for implementing WYSIWYG 1 printing technology. 1 What You See is What You Get 9

11 Photoshop 1 PS1 was small enough to send in an (857kb!) 2. The most recent version of PS requires around 1,000 times more space. 2 This screengrab was taken of PS1 running in emulation mode in my compurtor: 10

12 PS1 had no layers... 11

13 ...but layering was still possible using a blend mode (which were then called calculations )... 12

14 ...the composite calculation... 13

15 Voila! 14

16 Layers In 1991, Live Picture introduced layers to digital imaging 3. 3 http: //lensgarden.com/uncategorized/live-picture-software-that-was-way-ahead-of-its-time/ 15

17 In 1994, Adobe introduced its own version of layers in PS3. This was to be a game-changer, and heralded a huge raise in PS s popularity. Photoshopping was born!. 16

18 The Compositor s Workspace Introduction Some History The Compositor s Workspace Panels Workspace configuration Key Compositing Skills 17

19 First we need to configure PS so that it is friendly for a compositor s needs. 18

20 Panels PS comes with around 30 panels. This is what they all look like: 19

21 These are probably all you will need in this course: 20

22 Workspace configuration Please observe the following configuration: In OSX, arrange the dock so that hiding is turned on. 4 View/Snap = off (this stops items snapping to an invisible grid, which only a web designer would want) View/Rulers = off (Command :) Sample Size of Eyedropper Tool set to 5 by 5 Average (the default does a single point sample, which is too small for sampling from photos and suchlike) Key pallets are: Layers, Tools and Options (Windows menu), all others invisible Brush and Brush Presets Pallet visible via F5 In Brush Presets, set Build-up to on (Brushes are more fully described in my Photoshop Painting slides) View/Screen Mode to Full Screen Mode wth Tool Bar (F)

23 Key Compositing Skills Introduction Some History The Compositor s Workspace Key Compositing Skills Layer Clipping Blend Modes Adjustments Filters Masking 22

24 The following slides detail key compositing skills. Most contain links to my website, where these skills are addressed in more detail. 23

25 Layer Clipping Clipping is the first key skill. First of all, some basic terminology. In PS and compositing, we think of a composite as being composed of foreground and background layers (FG/BG). In the case of a simple portrait composite, the figure is the FG and everything else is the BG. A FG over a BG 24

26 Clipping masks a FG by the BG. 5 Place the cursor is placed between the FG/BG and it will turn into the clipping icon......the layers are now clipped!

27 One key function of layer clipping is to restrict a colour adjustment to only one layer. Hence many separate adjustments can be applied to a single layer, without affecting any other layer. In this example, clipped layers A effect layer B but not C. 26

28 Blend Modes Blend modes is the next key skill, and a very important one it is. A digital image is just (like its name suggests) a collection of numbers. A blend mode of two layers causes these two sets of numbers to act upon each other, like a maths expression. 6 The result can visually nuance an image: adding such things as texture, colour and shadow. 6 You don t need to know the maths behind this (though it is interesting). 27

29 Blend modes are found in a pull-down menu at the top of the layers pallet. This governs the blend mode of the selected layer. In the PS interface, almost everything happens in the Layers pallet

30 On the left below is a photo that has been multiplied by 0.5 using curves. On the right is the same multiplication performed by a layer set to Multiply. Its content has been filled with mid grey, which is a 0.5 in colour maths. See how they are identical? This demonstrates the simple maths behind a blend mode. Left: a multiplication performed with a Curve adjustment. Right: a multiplication performed with a Multiply blend mode. 29

31 Blend modes are divided into families: A B C D E F Normal Darken Lighten Contrast Comparative Value Based 30

32 Top tip: to get to know the effect of blend modes on an image, try applying to gradients. In the image below, three gradients are shown: A B C Ordinary Darkened by a gradient set to Color Burn blend mode Lightened by a gradient set to Color Dodge blend mode Two blend modes at work 31

33 Of course, some blend modes are more useful than others. I believe that the most useful are: Multiply, Screen, Color Dodge and Overlay. A list of blend modes, and my evaluation of their usefulness, is in my website

34 Adjustments A layer blend can change an image in complex ways defined by the BG layer blend. An adjustment from the Adjustments menu is more simple: changing the image in a uniform manner. 33

35 There are many adjustments... 34

36 However, only a few are useful... 35

37 The most useful Adjustments are: Levels Curves Hue/Saturation Invert Selective Color Most others should be ignored, especially the following, which are evil (I will explain why in class). Brightness/Contrast Color Balance 36

38 Levels plots the lightness values of an image as a histogram (a form of diagram that I will explain in class). This histogram can also be adjusted. More info on the Histogram is in my website 9 The Histogram

39 Curves is the one single adjustment that you cant live without. Furthermore, almost all serious digital apps feature a Curves adjustment, or something like it (e.g. in Nuke it is called ColorLookup). More info on the Curves is in my website 10 The Curves

40 A digital artist will become very sensitive to the shape of a curve. The curve below is a classic S shape, which performs a contrast adjustment on the image (i.e. darkens the darks and lightens the lights). More curve shapes here 11 Before An S shape curve (AKA a contrast curve) After 11 http: //opticalenquiry.com/photoshop/index.php?title=curves#visualizing_color_operations 39

41 A digital artist will become very sensitive to the shape of a curve. The curve below is a classic S shape, which performs a contrast adjustment on the image (i.e. darkens the darks and lightens the lights). More curve shapes in my website 12 Learn Curves! Learn Curves! Learn Curves! Learn Curves! Learn Curves! Learn Curves! Learn Curves! Learn Curves! Learn Curves! Learn Curves! Learn Curves! Learn Curves! Before adjust An S shape curve (AKA a contrast curve) After adjust 12 http: //opticalenquiry.com/photoshop/index.php?title=curves#visualizing_color_operations 40

42 Hue/Saturation performs an adjustment on the hue, saturation and lightness of an image. Of these, the most useful for image adjustment is the saturation. Do not use the lightness slider on a photo. Instead (ahem) LEARN CURVES. More on Hue/Saturation in my website 13. Hue/Saturation

43 Invert performs an inversion on the selected image. Its most useful application is in inverting a mask, which frequently need inverting. Its so simple, it doesn t even use a dialogue box. Just Command I. Invert has a cousin, which is selection invert: Command Shift I. 42

44 Selective Color is perhaps the most complex of all adjustments. It is the only decent way to change the hue of an image in a complex way. More on Selective Color in my website 14. Hue/Saturation

45 As with Blend Modes, the best way to learn Adjustments is on gradients. Below is a hue gradient the yellow of which has been tweaked in Selective Color to make it more pale. 44

46 Filters A Filter performs an adjustment on the pixels of an image in an uneven way (e.g. some and not others). Applied to a photo, generally a filter has a destructive effect. They can be used to generate effects and textures. 45

47 It is often the case that a single filter wont give you what you want. Rather filters have to be used in succession. The image set below shows a set of filters performed in succession. 46

48 Frankly, the most important Filters are the most boring ones, e.g. Gaussian Blur, Clouds etc. More on Filters in my website

49 Masking For a compositor, there is no more important, or demanding, key skill than masking. Masking serves to separate a region of an image from its neighbouring regions. 48

50 Using a mask, the background of a figure can be masked out and replaced with a new background. Using an eraser can achieve a superficially similar result, but offers far more flexibility. A figure against a background The figure masked out A new background placed behind the figure 49

51 At its most simple: the basic workflow is: 1 Selection 2 convert selection to mask 3 refine mask 50

52 First... you need to source an image that is suitable for masking. It should be of high resolution and have a clear foreground/background separation. The images below left is too low resolution. The foreground/background separation of the image below right is too poor. This image is too low resolution for masking Here the foreground/background separation is too poor 51

53 First... you need to source an image that is suitable for masking. It should be of high resolution and have a clear foreground/background separation. The images below left is too low resolution. The foreground/background separation of the image below right is too poor. Also... the top of both these heads is clipped, which makes them of limited use. This image is too low resolution for masking Here the foreground/background separation is too poor 52

54 1 Selection Photoshop has many selection tools16, but for this task the best is Select/Color Range. See my website for details http: //opticalenquiry.com/photoshop/index.php?title=selection_to_mask_workflow#select 53

55 You will now have a selection loaded into your image (the doted lines are called marching ants ). It is now ready for the... 54

56 2 Convert the selection to mask To convert the selection into a rough mask requires no more than pressing the mask button at the bottom of the Layers panel. 55

57 In this case, the mask has been created inverted (i.e. BG is masked out). To correct this, press Command i ( Image/Adjustment/Invert ). 56

58 3 Refine the mask To refine the mask, it is best that you view the mask clearly. To do so, option click inside it. This will make the mask visible in the main view. 57

59 Using the Brush tool, the Selection tools and your wit and wisdom, you add and remove from the mask. 58

60 Option-clicking again on the mask will return you to the RGB view. You can see that the figure is now separated from the background. 59

61 The mask will not be complete until you place the masked figure against its new background. The background will need to approximately match the figure in terms of colour and suchlike. 60

62 It is also likely that the figure will need to be adjusted to match. In this simple case, I added a clipped multiply layer (m) to darken the fringe, and an overlay layer (o) to adjust the colour. 61

63 To complete the whole process, you will need to work hard. The edges of the mask are super important, and are frequently made too sharp) Before After 18 More details here: Workflow#Edit_the_mask 19...and here: 62

64 - THE END - 62