Tài liệu The Photoshop Lightroom Workbook- P2 pdf

The Photoshop Lightroom Workbook and every photographer used Polaroid film on a shoot Operating systems continually change On the MAC side, we have gone from Panther to Tiger to Leopard in less than years No camera manufacturer has guaranteed that all current software will be backward compatible Files that opened up on your OS system may not open up today Digital needs to be as stable as film Only a standard file format can assure this for the future 32 Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark CHAPTER Color Spaces for Digital The Four Color Spaces for Digital T here are four color spaces that we will discuss: sRGB, Adobe98, ColorMatch and ProPhoto First, think about color spaces as boxes of Crayola crayons sRGB is the smallest box of crayons It has 256 tones The large box that many people choose can be thought of as Adobe98 It is like the big box of crayons with many shades of the same color The ColorMatch space can be thought of as a much bigger box than sRGB but not as big as Adobe98 Finally, there is the ProPhoto color space, which is so big that not all the colors can even fit in the box Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark 33 The Photoshop Lightroom Workbook Understanding Raw Digital Capture Raw files contain no color profile upon capture Once you bring those raw files into an image-processing software such as Lightroom, a color space needs to be designated ProPhoto is D-65’s choice for processing raw files We also set up our color settings in Photoshop with ProPhoto as our working RGB Why? Digital cameras today have come a long way in a very short time The sensors today are capable of capturing a very wide tonal range, but unfortunately, the majority of photographers simply don’t take advantage of the capabilities of their camera sensors and inadvertently throw out very important color information without even realizing it Your camera captures a wider range of colors than you can see The profile associated with the camera determines the colors available to be processed Your camera captures a wider range of colors than your monitor can display The profile associated with the monitor determines what colors presented to it are actually to be displayed Your camera captures a wider range of colors than your printer can print The profile associated with the printer determines which of the colors presented to it will be printed Let’s start with how most cameras actually capture color or rather don’t capture color The camera sensor doesn’t actually capture color at all The sensor captures in grayscale only It captures the intensity of the light in grayscale There are colored filters on the sensor such that a given pixel only sees light through a single colored filter: either red or green or blue Assuming you are shooting RAW, the job of the converter such as Lightroom, Adobe Camera Raw or Capture One is to interpolate data and render it as color If the pixel being interpolated is a ‘red’ pixel, that value is assigned red If the pixel being interpolated is a ‘green’ pixel, that value is assigned green, and if the pixel being interpolated is a ‘blue’ pixel, the value being assigned is blue With these three values, a color equivalent number can be calculated Every camera requires a profile or formula that can be used to translate the ‘zeros and ones’ that become color equivalent numbers Monitors and printers must recognize those numbers This translation is essentially the goal of your working space Okay, so in a more basic English, the color world we perceive with our eyes is captured by our cameras as light intensity in grayscale, 34 Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark Color Spaces for Digital translated into color by a special translator such as Lightroom and then passed on to our monitors, printers and all other devices Working Space for Digital The majority of photographers use Adobe98 as their working space While delivery in Adobe98 may be the so-called standard for delivery, it is not necessarily the ideal working space for digital photographers shooting RAW Why? ProPhoto can hold all the color the camera can capture plus more As cameras improve, they capture even more colors Every other color space, including Adobe98, will clip color from today’s cameras So that leads to the obvious question: What is clipping? In digital imaging, when a color falls outside the gamut or range, then we say that the color has been ‘clipped’ If we did nothing about the color, then it would be left out of the final image If we left these lost colors unattended, then our final image would come out, looking flat, due to the missing hues One of the biggest complaints of digital photographers is the loss of reds Well, when colors clip, red is the first to go ProPhoto preserves the widest range of reds A monitor can display colors that cannot be printed As well, paper can render colors the monitor cannot display Why would you want to limit printed colors just because your monitor can’t display them? Epson & Canon printers can print colors that are outside the Adobe98 space Using a ProPhoto space will obtain a greater range of tones and colors The bottom line is that Adobe98, or any color space except ProPhoto, does not preserve all the colors you get from the camera Once the file is converted, the extra shades are gone forever We must also look towards the future While your monitor of today can’t typically display all of the color in Adobe98, the monitors of tomorrow, and some of the more expensive monitors of today, display the full range of Adobe98 if not more For anyone using Adobe98, you must ask yourself the question: ‘Why would you want to eliminate extra color and tone just because your monitor of today can’t show it?’ Color Space for the Web The standard color space for the web for most monitors is sRGB The reason for this is because when the standards were defined, Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark 35 The Photoshop Lightroom Workbook sRGB was the largest space for any monitor As monitors get better, there may be less of a need for sRGB ColorMatch Color Space Another color space that is worth paying attention to is ColorMatch ColorMatch was defined by the old Radius Pressview monitors, which were an industry standard quite some time ago ColorMatch is very close to the gamut of CMYK Many photographers have difficulty converting to CMYK and complain about the correct color when the client does the CMYK conversions from Adobe98 for press Since ColorMatch is very close to CMYK, it makes a lot of sense to deliver in ColorMatch if CMYK is out of the question There is a problem delivering in Adobe98 for most client/ photographer relationships Here’s why…In the old days, when we delivered film, the art director or pre-press house scanned the film and made a proof Today, most art directors will receive a digital file in Adobe98 from a photographer This is where the problem starts Delivering in Adobe98 is sort of like saying ‘See all this color, well you can’t have it’ CMYK is a much smaller color space than Adobe98 Delivery in Adobe98 just about guarantees that the proof will not look like the image on the art director’s monitor The blame then falls on the photographer shooting digital If delivery occurred in ColorMatch, which is smaller than Adobe98 and very similar to CMYK, the proof will look very much like what is on the art director’s monitor The digital photographer will definitely be hired again Using Color Spaces and Profiles in Workflow With this in mind, it makes sense for digital photographers shooting RAW to make their Photoshop working space ProPhoto, to process their raw files as 16-bit ProPhoto and to store their archive files as ProPhoto ProPhoto is perfect for the digital photographer but not ready for prime-time TV for the rest of the world Because the majority of the world is in Adobe98, you certainly don’t want to deliver file to clients in ProPhoto For client delivery, you may want to convert into a color space that the client can handle Most clients are used to Adobe98 D-65’s 36 Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark Color Spaces for Digital recommendation is to convert the raw file using the ProPhoto color space during raw conversion and deliver in Adobe98 or ColorMatch This will allow the photographer to gain greater tonal range and color and preserve it achieving a better file Converting the file to Adobe or ColorMatch will preserve the greater tonal range and color while allowing the client to use the color space that they are used to Why ProPhoto? ● ● ● ● ● ProPhoto can hold all the colors that the camera can capture As cameras improve, they capture even more colors When colors clip, red is the first to go ProPhoto preserves the widest range of reds A monitor can display colors that cannot be printed Paper can render colors that the monitor cannot display Why would you want to limit printed colors just because your monitor can’t display them? Epson & Canon printers can print colors that are outside the Adobe98 space Using a ProPhoto space will obtain a greater range of tones The bottom line is that Adobe98 or any color space, except ProPhoto, does not preserve all the colors you get from the camera Once the file is converted, the extra shades are gone forever Color Spaces for Client Delivery Ideally, we would deliver images in CMYK using the ICC profile supplied by the client or printer Having the actual CMYK profile when we our color conversions will produce the best results However, much of the world disregards color profiles and/or doesn’t understand color management D-65 has a solution for these people too If we are going to deliver RGB images, D-65 will deliver files in ColorMatch ColorMatch most closely resembles what will be produced by CMYK output Delivering files in Adobe98 may look better on the screen but may contain more colors than can be printed So what you see is not going to be what your client will get in print Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark 37 The Photoshop Lightroom Workbook For images being used on the web or in multimedia presentations, D-65 will deliver files in the sRGB color space This limited space is the de facto standard for the web Demonstration on ProPhoto This is an image shot in ProPhoto and a graph of the image in the color analysis program, Chomix ColorThink (Figures 3.1, 3.2 and 3.3) (A) FIG 3.1 38 Map of the Image Color (B) Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark Color Spaces for Digital Orange out of gamut This graph displays our image plotted in Adobe98 Notice how much of the image is out of gamut, or outside the map of Adobe98 See the red out of gamut right here Blue out of gamut FIG 3.2 The graph displays the image mapped in ProPhoto and you will notice that ALL of the color is contained within the ProPhoto space FIG 3.3 One big problem with color management that always surfaces is how to handle files with different tagged color profiles or without any color profile When to Assign or Convert Profiles ● ● When opening a file, always assign a profile to an untagged (missing a profile) file If a file comes in without a profile, use your working RGB Convert from a source color profile to a destination color profile when you want to retain the color in a file but need it in a different color space For example, you would convert a ProPhoto file to sRGB when it is being used on the web It will still look like the ProPhoto file but will be tagged sRGB Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark 39 The Photoshop Lightroom Workbook ● A big misconception is that you can ‘go up’ or increase the color space of a file Photoshop will allow you to convert from sRGB (a smaller space) to ProPhoto (a larger one); however, the effect will be one NOT of additional colors but only of more tones of the same colors To summarize, Lightroom has really simplified many of the tough choices associated with processing For one, Lightroom uses a very wide color space, essentially ProPhoto RGB, but a gamma of 1.0 instead of 1.8 A gamma of 1.0 matches the native gamma of raw camera files, and ProPhoto is able to contain all of the colors that your camera is able to capture Since ProPhoto is really a 16-bit space, Lightroom uses a native bit depth of 16 bits per channel It makes sense to process your raw files in ProPhoto and to store your archive file as ProPhoto For client delivery, you will want to convert to the client-provided CMYK profile or, for a web press, U.S Web Coated (SWOP)v2 is a good default if you can’t get the ICC profile from the printer Use ColorMatch RGB for print or sRGB for the web D-65 does not deliver images in the ProPhoto color space because most clients would not know how to handle it Images in Lightroom can be in any color space and will be color managed, provided the image has an embedded profile If the image(s) you are working on does not have an imbedded profile, Lightroom will automatically assign sRGB without a warning dialog box Summary ● ● ● ● ● ● ● 40 There are four important color spaces for digital photographers They are from smallest to largest: sRGB, ColorMatch, Adobe98 and ProPhoto It makes sense to work in ProPhoto for digital imaging but deliver in ColorMatch or convert to CMYK for print If your images are going onto the web, sRGB is the correct color space Lightroom’s native color space is 16-bit ProPhoto Assign a profile when an image is not tagged with one Convert to profile when going from a larger color space to a smaller color space While Adobe98 may be the so-called standard, it isn’t necessarily the best color space for digital photographers capturing in RAW Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark Color Spaces for Digital Discussion Questions (1) Q What are the four major color spaces for digital photographers? A sRGB, ColorMatch, Adobe98 and ProPhoto (2) Q Why would you use ProPhoto as your working space if your monitor can’t display it? A While it is true that the monitors of today cannot typically display ProPhoto, monitors of the future will be able to display color spaces wider than Adobe98 Certain paper and ink combinations can already print a wider gamut than Adobe98 (3) Q What is the best color space for delivering to a client? A It all depends on the final use of the image If the image is going on the web, then sRGB is the correct space If the image is going to print, then ColorMatch is the best choice if you are delivering in RGB or to get the ICC profile from the printer and convert to CMYK Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark 41 ... and the Lightroom_ CatalogPreviews.lrdata These two files are the heart that makes Lightroom breathe The default location for this Lightroom folder is in your UserPictures folder The Lightroom_ CatalogPreviews.lrdata... outside the gamut or range, then we say that the color has been ‘clipped’ If we did nothing about the color, then it would be left out of the final image If we left these lost colors unattended, then... sRGB The reason for this is because when the standards were defined, Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark 35 The Photoshop Lightroom Workbook sRGB was the