Read Rgb of Fits File With Photoshop Cs5

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Handling Color-Infinite Conversions

Now that you've been introduced to the parts that brand upwards a color management system, you're ready to remember through the color-space conversions that volition come every bit y'all move documents through your workflow. The tools you'll use are the Color Settings dialog, which sets your defaults for colour conversions, the profile alerts when opening a document, the Convert to Profile and Assign Profile commands for converting colors at any time, and the Print dialog when yous're sending output directly to a printer.

Setting Upwardly Conversion Defaults (Policies)

You tin gear up color conversion defaults for each colour mode and command how the documents you lot open relate to your working spaces. Adobe has given these the bureaucratic-sounding name color management policies. Don't let the name intimidate yous; to ready them up, just respond these questions:

• What practise you want Photoshop to practice when you open or import an image that's missing a profile?
• What do you want Photoshop to do when yous open an image that has a dissimilar profile than the working space y'all chose?
• Practise you want Photoshop to allow y'all know when a profile is missing or doesn't match your working infinite?

Let'due south take a await at how the popular-upward menus and check boxes in the Color Direction Policies department (run across Figure 4-five) answer those questions.

Effigy 4-v Colour Management Policies let you tell Photoshop how documents you open should relate to your working space.

Handling Existing Profiles. The three pop-up menus all practice the same thing: They tell Photoshop what to do if the incoming image already has an embedded profile. When you have no doubt that incoming images are embedded with the correct profiles, Preserve Embedded Profiles is the safest choice, especially in a colour-managed workflow. Consider choosing Convert to Working RGB/CMYK/Gray when you expect to receive many images with dissimilar profiles and you'd like to standardize them to your working space by converting their colors as yous open them. In today'southward color-managed workflows, you lot typically practise not want to choose Off unless you lot take a very expert reason for deleting the profiles of all incoming images. When this selection is set to Off, Photoshop too does non embed profiles by default when you cull the New (document) or Salve Every bit commands.

Getting Notified. The bank check boxes in the Color Management Policies department are concerned with 1 thing: Do y'all want Photoshop to ask you what to practice when an incoming image doesn't match your color settings? If the answer is yeah, check the boxes, and you'll get to approve every potential conversion. Although this lets you maintain control, if you piece of work with many images, the alarm may announced with annoying frequency. If the answer is no, exit the boxes unchecked, and when there's a mismatch or missing contour, Photoshop volition simply execute the default treatment y'all prepare up with the popular-up menus to a higher place the check boxes. Unchecking the boxes works best if y'all trust that incoming images should always do what the pop-upward menus say in the outcome of a mismatch, because Photoshop is going to do that every fourth dimension, without asking y'all.

Let's walk through an instance. Suppose you lot turn off the check boxes, your RGB working space is Adobe RGB, and you set the RGB policy to Convert to Working RGB. At present let's say you open an sRGB epitome. The profile mismatch with your RGB working space causes Photoshop to implement your policy. Because you told Photoshop to catechumen images with mismatched profiles to your RGB working space, and yous turned off the cheque boxes, Photoshop volition get ahead and convert the sRGB image colors to Adobe RGB without telling you lot. If you had turned on the check boxes, Photoshop would have asked y'all before performing the conversion.

Handling Color When Opening an Image

If you checked the Inquire When Opening bank check boxes in the Color Settings dialog, you'll get to confirm the color management policy you set for the working infinite of an image you're opening; if you lot didn't check the boxes, Photoshop silently executes the policy (for instance, converting epitome colors into your working space). If you turned on Enquire When Pasting, you can control the conversion of images you paste or drag into a Photoshop document.

Responding to Warning Dialogs. If you lot turned on the Missing Profiles or Profile Mismatch check boxes in Color Management Policies, you'll see an alert dialog whenever yous open or import a document that has no profile or a dissimilar contour than your working space.

• Embedded Profile Mismatch means the incoming image has a different profile than your working infinite (see Figure four-6). That doesn't necessarily mean anything'south wrong. A contour is already embedded in the image, so the just question is whether y'all have a reason to change it. If you don't have a good reason to modify it, select "Use the embedded profile" and move on. If your project requires that all images be saved in a specific color infinite, such as sRGB for digital video or a specific CMYK press profile, and you've already gear up your working infinite to that contour, select "Convert document colors to the working infinite." The last selection, "Discard the embedded profile," may exist used in prepress workflows where profiles aren't used. Otherwise, avoid that pick in color-managed workflows, except when you're opening a printer profiling target. If you lot're not certain, click "Employ the embedded contour," click OK to go ahead and open it, and then see "When You lot Take No Idea What to Do" afterward in this affiliate to work out how to handle the image.

  

  Effigy 4-vi The Embedded Contour Mismatch warning offers iii choices for handling an image where the embedded profile differs from the working space.

• Missing Contour means what it says: The incoming file doesn't have an embedded profile (meet Figure 4-7). If you are using a traditional non-color-managed CMYK workflow where profiles are non used, you lot'll probably choose "Leave equally is." If you desire to outset color-managing the file, y'all get to assign a profile—either the electric current working space, or any profile on your computer—past choosing one from the "Assign profile" popular-up menu. If you need more assistance figuring out the correct answer to a missing profile warning, click "Get out as is," click OK, and so see "When Yous Take No Idea What to Do" later in this chapter.

  

  Figure 4-7 The Missing Profile warning offers three choices for treatment images that don't contain an embedded profile.

  "So catechumen certificate to working space" is a check box in the Missing Profile dialog. It'south useful when an prototype was previously edited in a colour space that didn't lucifer your working infinite. It lets yous first assign the previous colour space of the image and so that the colors look normal. Then, past checking the box, you can convert the epitome into your working infinite. If you know that the image with the missing contour was previously edited in your working space, you lot don't demand this check box, because yous can simply select "Assign working space."

  Be enlightened that if you choose "Discard the embedded contour" or "Leave as is," not only volition the document exist opened without a contour, but Photoshop will not embed a profile into the certificate when y'all save information technology. If you want a profile to be embedded without converting the colors, choose "Utilise the embedded contour" or an "Assign profile" option, depending on the alarm.

• Paste Profile Mismatch may appear if yous paste from a certificate that uses a different colour space from the one you're pasting into (see Effigy 4-8). Because it's coming from the Clipboard and not from a saved file, assigning isn't possible; the just selection is whether or non to catechumen. In a color-managed workflow, you typically want to click Convert and then that the appearance of the pasted data doesn't change.

  

  Figure 4-viii The Paste Profile Mismatch warning lets yous choose whether to paste the numeric values or the perceived colors that those values correspond.

Converting Colors for Output

When you print, the Print dialog uses the document infinite every bit the starting point and gives you the opportunity to convert to a print profile or whatever other profile. This is covered more than specifically in "Converting Colors When Yous Print" later in this chapter.

There may be times when y'all need to convert colors for a Photoshop document for someone else to impress. Since you're not going through the Print dialog yourself, y'all'd utilise the Catechumen to Profile control instead (run into "Catechumen to Profile" subsequently in this affiliate). For example, y'all might be sending an image to a publication that requires that images be converted to their CMYK printer profile, while the certificate infinite of your images is Adobe RGB. To take care of this, yous'd duplicate the original document and convert the copy's colors to the printer's CMYK profile.

When you employ the Salve for Spider web and Devices command, a Catechumen to sRGB check box in that dialog lets you convert colors to sRGB, so that y'all don't have to call back to utilise Convert to Profile in advance.

Rendering Intents

Each device has a fixed range of color that it tin reproduce, dictated by the laws of physics. Your monitor tin can't reproduce a more saturated red than the red produced by the color filter or phosphor that a monitor uses to produce red. Your printer can't reproduce a cyan more saturated than the printer's cyan ink, or a white brighter than the white of the paper. The range of colour a device can reproduce is called the color gamut. Colors nowadays in the source space that aren't reproducible in the destination space are called out-of-gamut colors. Since you lot can't reproduce those colors in the destination space, you have to supersede them with some other colors.

The ICC profile specification includes four methods of handling out-of-gamut colors, chosen rendering intents. (You might see them referred to in Photoshop simply as "intents.") The 4 rendering intents are equally follows:

• Perceptual. This fits the gamut of the source space into the gamut of the destination space then that the overall color relationships and, hence, the overall prototype appearance are preserved, even though all the colors in the image may change somewhat in lightness and saturation. Information technology's a skillful choice for images that contain significant out-of-gamut colors.
• Saturation. This maps fully saturated colors in the source to fully saturated colors in the destination without concerning itself with hue or lightness. Information technology's mostly skillful for pie charts and such, where you lot just desire bright colors. You tin can also attempt it equally an alternative method of perceptual rendering. It may be worth previewing a conversion using Saturation rendering to see if information technology does something useful. For more information on doing that, see "Soft-Proofing Other Color Spaces," later in this chapter.
• Relative Colorimetric. This maps white in the source to white in the destination, and then that white on your output is the white of the newspaper rather than the white of the source space, which may exist different. Information technology then reproduces all the in-gamut colors exactly, clipping out-of-gamut colors to the closest reproducible hue. For images that don't contain significant out-of-gamut colors, it's often a ameliorate selection than Perceptual because it preserves more of the original colors. But if an image has many out-of-gamut colors, they're merely clipped, so Perceptual might be a ameliorate choice for those types of images.
• Accented Colorimetric. The Absolute Colorimetric intent is the same every bit Relative Colorimetric, except that it doesn't scale source white to destination white. If your source infinite has a bluish white and your output is on a yellowish-white paper, Absolute Colorimetric rendering makes the printer lay downwards some cyan ink in the white areas to simulate the white of the original. It'southward more often than not used only for proofing (run into "Soft-Proofing Other Color Spaces" later in this chapter).

Embedding Profiles

Embedding a profile simply means you're including information technology in a document when you lot save information technology. In the Save As dialog (see Figure four-ix), the Embed Color Profile bank check box embeds the profile. When y'all create a Web image, the File > Save for Web & Devices dialog contains an Embed Colour Profile check box. If you relieve or export a file and the profile option is unavailable, information technology means yous've selected a format (such as GIF or BMP) that tin can't embed a profile.

Figure 4-9 To include a contour equally y'all save a document, plow on the Embed Color Profile check box near the bottom of the Save As dialog. Photoshop ever tells you which contour will be embedded.

When Not to Embed Profiles

I've advocated embedded profiles then much that you might remember I e'er do information technology. Well, by and large, but in that location are a few cases in which I don't.

For example, I didn't embed profiles in any of the CMYK images used in this book, because they were all going to the same printing condition, and I fix InDesign's CMYK working space to the profile that describes that press condition. The CMYK profile for this book is about 2.8 MB, so past not embedding it in every epitome, I saved a significant corporeality of disk space and FTP transmission time. The CMYK numbers are unambiguous, because they're governed past the working space profile for the InDesign document.

For Web images, I typically don't embed profiles. Instead, I convert the images to sRGB and exit it at that. About of the few Spider web browsers that use ICC profiles have that feature turned off by default, and when fast page loading is a priority, including profiles works against that goal past increasing the file size of images. This is changing, though; as more browsers support profiles past default information technology may become more than applied to include profiles in Web images. For now, I include profiles just if I know that the master audition of the Web page uses a browser that'due south color-managed by default (such equally Safari), or if the image is so large that including a contour would exist a relatively small function of its file size.

When working with profiling targets, the whole point of the practice is to find out what colors the device in question produces when it's fed the color numbers in the target, and then there's no point in making any assumptions most the appearance represented by the numbers. Therefore, no contour.

Final simply not least, if you're working in a closed-loop CMYK workflow, where you only don't want the CMYK numbers to change when sent to your press procedure, there's no betoken in embedding a profile.

In all other situations, embedding profiles in your images is strongly recommended. This conveys your color intentions clearly to all the devices and all the people in your workflow. If you don't, the people downstream have to estimate your intentions, causing actress work and frustration for all concerned.

Using Color Settings Presets

In the Settings pop-upwardly carte at the top of the Colour Settings dialog, you lot can choose a single preset that sets working spaces, policies, and warnings for you lot all at in one case (see Figure 4-x). The real power of the Settings pop-up menu isn't in the settings Photoshop provides, which is why y'all haven't read about information technology hither until now. Instead, it'due south in the ability it gives you lot to save your own settings to disk then retrieve them quickly later. Even better, although you can always load a Color Settings preset from anywhere on your difficult bulldoze (using the Load button), if you save your settings in the right identify, they become available from the Settings popular-up menu. (In Mac Bone X, the "right place" is inside the Library\Awarding Support\Adobe\Color\Settings folder; in Windows 7, it's inside Users\[username]\AppData\Roaming\Adobe\Color\Settings.)

Figure iv-10 In the Color Settings dialog, clicking the More than Options push button extends the dialog and the choices in the pop-up menus.

Saving presets that appear in the Settings bill of fare offers an easy manner to configure Photoshop for an entire workgroup. And if y'all own the entire Creative Suite, you can even synchronize the color settings to the same preset beyond all the Artistic Suite applications: In Bridge, choose Edit > Creative Suite Color Settings, and click Synchronize Color Settings.

The presets that Adobe offers fall into two wide categories: those that ignore color direction and those that use it.

Full general Purpose two. The three General Purpose two presets (North America, Europe, and Japan) set up the RGB working space to sRGB; they set the CMYK working space to U.S. Web Coated (SWOP) v2 (North America), Euroscale Coated v2 (Europe), or Nihon Color 2001 Coated (Japan); they set up the Grey working space to Dot Gain 20%; and they gear up all the policies to Preserve Embedded Profiles while disabling the contour warnings.

What's the "two" all well-nigh? These presets are an improvement over the General Purpose Default settings that commencement appeared in Photoshop CS. The version 2 settings preserve embedded profiles for all colour modes (which ways the prototype is displayed in the aforementioned way it was when it was last saved), and they no longer use a dissimilar default rendering intent than all the other presets. The default rendering intent for all Photoshop CS4 presets is Relative Colorimetric with black-point compensation.

Northward American Paper. This preset, new in Photoshop CS5, uses the US Newsprint (SNAP 2007) profile as the CMYK working infinite. To more closely match newsprint characteristics, the Grayness and Spot dot gain values are college than in the Prepress two presets, and the default Intent for color conversions is set to Perceptual to scale colors down to the color gamut of newsprint, which is so small compared to higher-quality paper stocks.

Prepress two. The three prepress settings—Europe, Japan, and N America Prepress 2—tell Photoshop to use color management wherever possible and to plow on all the alerts for missing and mismatched profiles. They differ only in their choice of CMYK profiles and the dot gain for grayscale and spot colors (20 per centum in the United states of america and 15 percentage in Europe and Nihon). If your work is destined for a printing press and you don't have a custom profile for your printing or proofing conditions, ane of these choices may exist a good starting point.

The Northward America and Japan Prepress 2 presets are identical to the prepress defaults that shipped with Photoshop CS. The Europe Prepress 2 preset uses the Europe ISO Coated FOGRA27 CMYK contour as the CMYK working space instead of the older Euroscale Coated v2. The older profile didn't really match a standardized printing condition, so version 2 is an improvement.

Monitor Colour. As its name suggests, Monitor Colour loads your monitor contour as the RGB working space and tells Photoshop not to use color management, setting all policies to Off. It treats all your documents every bit though they are in the working space for that color fashion, ignoring whatever embedded profiles. For some inexplicable reason, though, it turns on the Profile Mismatches: Ask When Opening alarm, which makes no sense, since the contour will be ignored anyway.

Spider web/Internet. If you prepare images exclusively for the World Wide Spider web, the new Web/Internet presets (one each for North America, Europe, and Nippon) may be quite useful. The Web is, of course, the aforementioned in Japan as it is in Due north America or Europe: The but difference between the three presets is the CMYK working infinite, which is U.S. Web Coated (SWOP) v2 for North America, Japan Color 2001 Coated for Japan, and Europe ISO Coated FOGRA27 for Europe.

The unsafe aspect of the Spider web/Cyberspace presets is that they set the policy for RGB to Convert to Working RGB. That's probably OK if all your work is destined for the Web, but since it automatically converts every RGB file to sRGB, you'll be unhappy when larger-gamut RGB images destined for impress get squashed into sRGB! At to the lowest degree the profile mismatch warnings are turned on for this preset; pay attention when they appear.

The Obscure Color Settings Options

When you click the More Options button in the Color Settings dialog, yous gain access to the Conversion Options and Advanced Controls, too as to a wider range of profiles, which were discussed before in this chapter. The Conversion Options can be useful in typical workflows, but the Advanced Controls are a grab bag of options that may be useful to a very small number of serious players and are dangerous for almost everyone else.

Conversion Options and Advanced Controls

The Conversion Options section of the dialog lets you control useful things like the default rendering intent in Photoshop and the color management module (CMM)—things you may never need to change (meet Figure four-11).

Figure 4-11 The Conversion Options let yous fine-tune how Photoshop performs color conversions.

Engine. The Engine pop-up card lets y'all select the CMM that Photoshop uses for all its color-infinite calculations. The options that appear on the carte depend on which CMMs are installed on your arrangement. Unless you have really pressing reasons to utilize a dissimilar CMM, stick with the Adobe Colour Engine (ACE). When the engines work correctly, in that location is only a tiny change in pixel values amid the dissimilar engines with no noticeable visual departure. Mac users will see separate entries for the Apple CMM and Apple ColorSync; Apple tree CMM means that the Apple CMM will e'er exist used.

Intent. The Intent pop-up carte lets you choose the default rendering intent that Photoshop uses when you convert colors equally you lot open a document or alter the color fashion on the Image > Way submenu (such as when you catechumen from RGB to CMYK). It also affects Photoshop'south calculation of colour value readouts for color modes other than the certificate'due south, such as in the Info console and the Colour Picker.

While it's dainty to exist able to gear up the default rendering intent, intent is all-time treated every bit an prototype-specific and conversion-specific decision. In many places in Photoshop, yous can preview and modify the rendering intent to suit the needs of the image at hand.

Use Black Point Bounty. The Use Blackness Point Compensation option maps the black of the source contour to the blackness of the destination contour, ensuring that the entire dynamic range of the output device is used. It'due south more often than not a good idea to go out Use Black Betoken Bounty turned on unless you have a proficient reason to turn it off. Depending on the contents of the profiles involved, in many cases y'all'll find no difference whether this setting is turned on or off. Irresolute this setting tin be one thing to try when shadow areas seem off or don't convert as y'all expected.

Employ Dither (eight Fleck/Channel Images). All color-space conversions in Photoshop are performed in a high-fleck space. When Apply Dither is turned on, Photoshop adds a small corporeality of noise when the viii-bit channels are converted into the loftier-bit space, making banding or posterization much less likely to occur (that'due south a good matter). Merely if your final output volition be JPEG, this tiny dithering may cause a larger file size (because it adds discrete colors into the image). If you lot're using Photoshop for scientific work, where you demand to perform quantitative analysis on colors, you lot should turn Use Dither off, as dithering will introduce dissonance in your data; otherwise, leave it on.

Compensate for Scene-Referred Profiles. If you use Photoshop to create documents for the Adobe After Effects move-graphics awarding and Later Effects is set to its default color management settings, you lot'll want to turn this option on. For everyone else, it doesn't affair how you set information technology.

The Advanced options are named Avant-garde for a reason; almost users should not need to touch them.

Desaturate Monitor Colors By. Unless you lot're working with a very large space, like ProPhoto RGB, avoid touching this selection. Monitor display is always Relative Colorimetric, and so any working infinite colors that are outside the monitor'due south gamut must be clipped to the nearest equivalent that the monitor can display. This choice scales downwardly the saturation of brandish colors to effort to become around the problem, but it isn't normally used—the problem it tries to work effectually is non as bad equally theory would lead one to look. If you practise want to try it, a setting in the 12 percent to xv percentage range seems somewhat useful for the ProPhoto RGB colour space.

Blend RGB Colors Using Gamma. To run across the event of this option, paint a bright dark-green stroke on a red background with the cheque box turned off, and so again with the cheque box turned on and the value set to a gamma of 1.0. With the cheque box turned off, the edges of the stroke accept a brownish hue, every bit they would if you were painting with paint. With it turned on, the edges are yellowish, every bit they would be if y'all were painting with light. You lot can think of the behavior with the check box off as artistically correct, and with it turned on every bit colorimetrically correct.

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