A few words about myself ... I have been doing desktop publishing and prepress since 1990, and first encountered Acrobat in 1994. Over the past 25 years, I haven’t tired of discovering its capabilities, and had a chance to do this as a head of agency prepress departments and publishing houses and consultant on Acrobat in Russia by Adobe itself. I have something to share about Acrobat and PDF - let's get started! Let's go from simple to complex and cover everything important from the initial settings to working with color and solving specific questions in the Preflight panel, but everything in good time: check back regularly in late 2020 and early 2021 as new articles are released.
Brief historical background (curious can read more here): Acrobat and PDF originated at the same time. In the early 1990s, John Warnock, one of the two founders of Adobe, was looking for a solution to the problem of reliably transferring documents between different computers, operating systems and, at the same time, paper media - without changing their appearance or depending on external conditions (for example, having the right fonts) ... This work culminated in 1993 with the release of the Portable Document Format, which was destined to revolutionize the way the world deals with documents. But it was the prepress industry that drew attention to it first. the format was essentially an ideal "digital printout" with all the data necessary for reliable output in a single file: text with fonts, images, vector objects + support for the CMYK color model.The reprint specialists did not need to explain these advantages: they already had it all thanks to PostScript, also an Adobe product (by the way, the very first one for which the company was created in 1982). But here's the bad luck: PostScript could not be “seen” and was convenient check, it is a printer command language that creates graphics step by step, rather than fixing its description. PDF has become a bit of an evolution, a bit of a revolution for PostScript, adding fast and reliable visualization of graphical information by eliminating printer commands and developing the narrative in a compact, versatile form. New applications for Mac OS, Windows, DOS, OS / 2, Unix - Acrobat Reader and Acrobat Distiller were responsible for this visualization.the very first, for the launch of which the company was founded in 1982) But here's the problem: PostScript could not be "seen" and easy to control, it is a printer command language that creates graphics step by step, and does not fix its description. PDF has become a bit of an evolution, a bit of a revolution for PostScript, adding fast and reliable rendering of graphical information by eliminating printer commands and developing the narrative into a compact, versatile form. New applications for Mac OS, Windows, DOS, OS / 2, Unix - Acrobat Reader and Acrobat Distiller were responsible for this visualization.the very first, for the launch of which the company was created in 1982) But here's the bad luck: PostScript could not be "seen" and easy to control, it is a printer command language that creates graphics step by step, and does not fix its description. PDF has become a bit of an evolution, a bit of a revolution for PostScript, adding fast and reliable visualization of graphical information by eliminating printer commands and developing the narrative in a compact, versatile form. New applications for Mac OS, Windows, DOS, OS / 2, Unix - Acrobat Reader and Acrobat Distiller were responsible for this visualization.PDF has become a bit of an evolution, a bit of a revolution for PostScript, adding fast and reliable visualization of graphical information by eliminating printer commands and developing the narrative in a compact, versatile form. New applications for Mac OS, Windows, DOS, OS / 2, Unix - Acrobat Reader and Acrobat Distiller were responsible for this visualization.PDF has become a bit of an evolution, a bit of a revolution for PostScript, adding fast and reliable rendering of graphical information by eliminating printer commands and developing the narrative into a compact, versatile form. New applications for Mac OS, Windows, DOS, OS / 2, Unix - Acrobat Reader and Acrobat Distiller were responsible for this visualization.
The first provided rendering - that same display of PDF data on all systems, the second turned any PostScript and EPS materials available to PDF. The only thing left to do was to output data to PS from graphic applications or print to PDF from ordinary ones via the included PDF driver (more precisely, first in PS, but this is under the hood).
The familiar era of modern prepress began, in which, as PDF support was added to raster processors and the development of PostScript and PDF formats, at first they went hand in hand, but gradually PDF squeezed out its big brother, retaining its relevance only in narrow applications. And Acrobat has become one of the premier prepressor tools with comprehensive support for all PDF creation and manipulation capabilities.
Settings to control and troubleshoot PDFs for predictable printing
In this first article, we will take a look at the application settings for validating PDF files as expected and not crashing. We will immediately agree to use the names of the Russian Acrobat interface, even if the translation cannot be considered successful or at least the same in different places of the program. I myself, frankly speaking, prefer English interfaces for the sake of accuracy and brevity of terms, and I always recommend getting used to them, even if you do not speak English well - this will help to improve the language, and most importantly, it is easier to work with a huge array of useful information on prepress on the English-speaking Internet compared to Runet. Anyway, since 2012, Acrobat allows you to freely switch interface languages in Preferences> Language> Application Language. Like many other teams,You can call the settings through keyboard shortcuts - we will not discuss them in the article, but put aside useful links and try to use them: you will give yourself many hours of saved time.
Further, I will not indicate English-language links if there are Russian ones, but I will share a life hack: in the articles of the Adobe online help, it is enough to remove the “ru /” node from the link to open the article in English. Try the examples above.
Installations
So, let's start with setting up the working environment - this is very important for fast work and setting the correct behavior of tools. We will not be able to discuss everything, we will only touch on things that directly affect the prepress.
Section "Units of measurement"
When choosing the Russian interface language, the latest versions of Acrobat automatically include millimeters as the main units of measurement. If it needs to be changed, this is done in this section. At the same time, you can change the color of the grid lines or guides if you use them and in a specific document they are lost against the background of the images.
Section "Page layout"
This group of settings is not very intuitively named, but it is very important - let's analyze everything in detail.
Page layout. In each PDF file, you can set its appearance on opening ( File> Properties> Appearance on Open ). In particular, layout and scale: the number and order of pages on the screen and their initial size. This is very useful when checking documents with covers or organized exercise books. For example, single pages or spreads, page fit in width or height, or in real scale. But in cases where such parameters are not specified in the file itself, the installation from this section will work - however, there is an important subtlety. If you can explicitly set the behavior of the first page when displayed in spreads (View Mode> Double> Title Page / Spreads ), and as a result, either odd pages like in books and magazines, or even pages will go first in the spread, then in the Page Layout settings you can only select "Page Layout" or "Double". But even in this case, you can influence the behavior of the first page: it will be set by setting in the View> Page layout> Show cover page when displaying two pages , if you enable it in an empty application and no documents are open.
This logic can be interfered with by the installation from the "Documents" section : Open the options window> Restore previous view options when opening documents... It is better to keep it off, because when you turn it on, it remembers the last display settings for each opened document. This not only litters the disk with unnecessary information, but also interferes with testing the document's appearance settings when opening - when they are updated, they will not work in documents that you have already opened before, if this option is enabled.
Resolution.This is a key setting if you need to work with documents in their actual physical size. Obviously, for these purposes, you set the scale to 100% (I recommend this as the default value), but this is 100% of what value? To bring the screen dimensions to physical, Acrobat needs to understand the real resolution of your screen - for this, this setting is proposed. On laptops and modern LCD monitors, the system setting is often correct, but if not, or if you are distracted by small deviations, you can achieve a 100% hit by manually specifying the real resolution (in ppi - pixels per inch) in the Custom Resolution field. And one more thing about the 100% scale - in the Russian interface it is mistakenly indicated in the "Scale" drop-down list as 10%, but it doesn't matter: just type "100%" manually.
Rendering.This group of parameters directly affects the ability to detect defects in files for printing. Many people remember raster processors that did not support transparency processing - they required files according to the PDF 1.3 or PDF / X-1a specification, for which the transparency effects had to be pre-rasterized ("flattened"). This led to the appearance of hundreds and even thousands of small images with vector masks and a radical complication of the document with a high load on the computer memory and raster processor. Conclusions from this: when working with such files, try not to use the "page cache" (background rendering of the next page when viewing the current one) and be careful when turning on "image smoothing" and "line art smoothing"(vectors). These functions make bitmaps and vector drawings as pleasing to the eye as possible, but can lead to the appearance of "ghosts": visible on the screen, but not existing and not displayed on the plates gaps between the very fragments of images formed when flattening transparency. It is usually more practical to keep these settings enabled, but if in some cases you are "plagued by vague doubts", open Settings and temporarily disable them. If this does not calm you down, to check it, do it for RIP: render the problem page in Photoshop with RIP resolution (2400 / 3600dpi) - strictly without anti-aliasing enabled. If you don’t see the "ghosts" anymore - do not hesitate to send the page for withdrawal.
Two more attitudes in this group can give false peace of mind when there are problems. "Enhance Thin Lines" is convenient for viewing, but if somewhere in the PDF there are lines less than 0.1 point thick, then you will have problems with output. It is important to check this both automatically using Preflight (more on this later), and simply to see with your eyes. If you enable this option, Acrobat will render these lines thicker and you will skip the problem. It is safer to disable this option and see everything as it is (or even not see this line where expected).
Use Local Fonts- another convenience trap. For the sake of self-sufficiency in PDFs, it is important to embed all the fonts used in it, although the possibility of not doing this sometimes tempts fans to reduce the file size. If the font is not embedded, it must be available to the bitmap processor at the rendering stage, but since in most cases this is not the case, a substitution will occur and the result will be sent to the basket. It is important to notice such substitutions when controlling in Acrobat, and disable this option - otherwise the required font, possibly installed locally on your system, will perfectly connect in the document. This will skip the substitution. But of course, such moments cannot be trusted with the eye of the operator: verification of font embedding must also be included in the automatic preflight procedures. As for optimizing file size,you can safely use font subsetting - automatic creation of selections of only characters actually used in each document (especially after slicing a multi-line file into single-page ones, if you often need it). If you are concerned about the inability to use the document editing capabilities of Acrobat, do not worry: Acrobat will not allow this even with a fully embedded font due to the limitations of the font license: editing is only possible with locally installed fonts (and does not depend on the inclusion of the option we are discussing). If you need to edit a PDF with an embedded font that you don't have, only Enfocus PitStop Pro, which is also sold at Softline and which is more reckless than Acrobat when it comes to digital copyright, will help you out. Maybe before the first use case:Adobe learned its lesson in a legally painful way, even though it was at the forefront of the early digital font licenses.
At the end of the conversation about fonts, I will add that old superstitions from PostScript times about the incompatibility of TrueType (.ttf) fonts with serious prepress have sunk into oblivion: if the quality of the font itself does not cause any complaints, you can safely use and display it. The PDF format supports all modern font formats, except for web fonts (EOT / WOFF / 2), and both PostScript fonts and TrueType or OpenType are equally native to it as a container for the first two - in the structure of the PDF file, fonts are presented special way. And since Since 2007 PDF is a standard of the International Organization for Standardization (ISO), manufacturers of raster processors have no choice to support or not support its individual features: here it is all or nothing.
Always show page size
The option speaks for itself, it is important to just remember that it is. Older versions of Acrobat have always reflected size, while newer versions must be explicitly included here. The size will always be visible in the lower left corner of the window.
Show artwork borders, clipping frame and bleed area
Raster processors can adjust the crop size in different ways: sometimes explicitly, so that the input pages are simply centered in the work area. But more often, RIP relies on the sizes specified in each PDF page, which are divided into 5 types:
- Art box ("illustration", red guides) - the common outer border of all objects. Has no practical application
- Trim box (green guides) - trim size. The boundaries along which the knife will pass when trimming a notebook or finished product.
- Bleed box (« », ) — . , , 2 : , ?
- Media box ( ) — «» . , ., , .
- Crop box ("cropping", black guides) - the border of the area visible on the screen. It is indirectly related to prepress: for example, the file can contain both episodes and fiducial marks, but you can set the crop box equal to the trim box, and then nothing outside the image format will be visible on the screen in Acrobat. However, the printing house will display everything that fits into the bleed / media box or was set in the raster processor. So get in the habit of checking to see if you can see in front of you (and when displaying the size in the corner) the entire page, or just the crop box.
A visual indicator for this is the special guides of the specified colors, familiar to everyone from the "Set Page Margins" clipping dialog. And the setup we are discussing allows them to be displayed constantly on every open page - this removes many questions.
Show transparency grid
Another option with a self-explanatory name, about which it is important to remember that it is. If you often work with PDF files that are not for output, but for insertion into other applications, or open Illustrator files (.ai) in Acrobat, which in most cases are nothing more than PDF with some private appendages, then it happens it is useful to understand where the page has a solid white background and where is the empty area that will be transparent when inserted. This option allows such blank areas to be displayed in the same way that Photoshop and other tools display transparency - a gray checkerboard grid.
Use logical page numbers
Logical numbers are a big help. They allow you to mark up sections in documents for easy navigation and understanding of the structure. Benefits for pre-printing - situations when eg. different sections are printed on different paper and should be displayed in separate notebooks. But more often than not, it is necessary to mark up the covers so that they separate from the block. You can, as in the example, set the prefixes "region." the first two and the last two pages of the brochure to make it clear to the typographer how to handle the document.
The ability to access the desired page by logical number is precisely set by this setting. In our example, this means going to the page shown on the left under number 1, either by this number 1, or by number 3 (ordinal in the document).
Let's see right away how the numbering is set, because in the Russian interface it is not very clear. In the "Page Thumbnails" panel , select the desired page range and right-click to call the context menu; it contains the "Page Shortcuts ..." command , which will finally show the "Page Numbering" dialog .
Reference XObject Options
The PDF 1.4 standard (and PDF / X-5) allows the use of inserts from external documents in the form of special reference links (although this is not the only purpose of the XObject structure: it also provides the reuse of repeated fragments within the same file - for example, for correct fills. patterns). This feature is quite fragile, it requires guaranteed availability of external files, special permissions to access their storage location, and special tools for creating such files. With a high probability, you will not come across PDF files with external X-objects in your practice, so you can not be afraid of incorrect settings in this field and leave everything by default.
Use overprint preview
It's about old friends - overprints. Hello from the days of PostScript, when it was the only way to color blend with its own set of subtleties and caveats, before the arrival of transparency with PDF 1.4. Unlike transparency, overprint rendering was and still needs to be explicitly enabled in Illustrator and Acrobat, which is what this option does. If this is not done, you may not see the applied overprints, and the consequences can be dire - it is no accident that when you were hired, you were probably asked about the consequences of overprints on white objects ... This setting allows you to enable the display of overprints for any files or only for PDF / X, the printed purpose of which is already clear. Or disable it permanently.
Select multiple items by pressing Shift and clicking the mouse at the same time
This unreadable option, not even worth mentioning in the online help, relates to the very convenient ability to add non-printable prepress comments to a document. Here it is necessary to take a step aside to clarify what it is about.
The fact is that since 2012 and the version of Acrobat Pro XI, when working in the Separation Preview panel, there is a very convenient opportunity to fix the results displayed in the panel locally right in the context of the page using notes:
The note was inserted by Shift-clicking in the place of interest. But since The Separations Preview window is modal and can hang open while you are busy with other things, its "grabbing" the Shift key made it impossible to use it to select multiple objects. To correct this inconsistency, such a setting was added - when it is turned on, the "Preview Separations" notes are added by Alt-clicking. Without it - as before, by Shift-clicking. And by the way, the dialog "View Color Separations" itself is not only about color separation, but more on that later.
Color manager and color management
These color management settings work by default if RGB, CMYK, and Grayscale objects in the file are not individually tagged with color profiles, or if the target color profile of the Output Intent (completely inadequately translated as "Output Method") is not specified at the document-specific level . In other words, “just RGB” or “just CMYK” will appear in Acrobat as if all color coordinates were specified in the color spaces specified here.
It's important to remember about exceptions. The main thing is all PDF / X files, because the standard obliges them to have an explicitly specified target Output Intent. It is usually set via the built-in ICC profile, but there is a subtlety here. In my practice, I avoided this method, because high-quality CMYK ICC profiles are quite heavy, 2 MB or more. While printers often require submitting materials in one-page PDFs to simplify their lives, this means that each file will increase in size by that figure. For a 100-page magazine, that's +200 MB of excess weight and download time. If for someone this is an urgent question, there is an alternative: Output Intent can be set not by embedding a profile, but by simply mentioning one of the standard Output Intents through the so-called. Output Condition Identifier - all Adobe applications and Acrobat itself can do this when processing PDF / X.This is a set of typical printing conditions with standard names, and it is enough to mention one of these names, and Acrobat or another prepress application or RIP will independently substitute a suitable profile according tothe ICC registry (in this table, the Output Condition Identifier is specified in the "Characterization data reference" field). It should be borne in mind that this is still a rather fragile process, because you can make a mistake in the name or the profile for substitution may be outdated or not configured at all in RIP or configured, but physically inaccessible - however, it will be he who will be responsible for converting to CMYK of any PDF objects specified in other color models.
Output Condition Identifiers relate to the most common printing processes and papers. While it is certainly desirable to work with custom ICC profiles created for every combination of paper, ink, and print conditions, it is often an unaffordable luxury. Usually, very carefully crafted profiles of international organizations on print standards come to the rescue. They are regularly updated and are perfect in most cases when a printing house claims work in accordance with one of the standards ISO 12647, FOGRA, CGATS, etc. Follow the link to select and download the correct profile for your work.
Exceptions that do not cover general color settings include direct selection of a profile for screen proof in Separation Preview- they can be freely switched to check how the color rendition will change in different printing conditions (which, in fact, is fixed by the CMYK ICC profile). Also, it is no longer imitation, but transformation into the desired color space while maintaining color rendition is offered by the "Convert Colors" panel , which we will talk about in detail. About it you need to understand that the further color behavior in the converted file relative to the general Acrobat settings is determined by the "Embed" checkbox. If enabled, the target profile will become the Output Intent for this document with all the consequences that we discussed for PDF / X.
Of course, Preflight fixtures also allow you to manipulate color. But it is the most powerful tool in Acrobat, and it requires attention to the finer points of color management: in each case, the decision will be in your hands.
Finally, consider the ability of the free Adobe Bridge media manager to synchronously manage color presets across all Adobe Creative Cloud applications, including Acrobat Pro. Although, as you can see, you can manually connect the profiles of the desired color spaces, it is often important to do the same in applications such as InDesign, Illustrator or Photoshop - and this is the task of synchronous switching Bridge takes over. If you call its menu "Edit> Color Settings", select one of the sets of color settings in it and click Apply, then the changes will be applied synchronously in all installed Creative Cloud applications. And Photoshop allows you to create such sets of settings, and only in it, in the working color space settings for the Grayscale model, you can load a CMYK profile and convert it into a single-channel Grayscale profile, with which you can simulate a one-color black print on the screen with real parameters of dot gain and ink absorption.
Section "Documents"
In addition to the already mentioned option "Restore the previous view settings when opening documents", it is useful to disable "When executing the" Save As "command, optimize for quick viewing in a web browser". This option rebuilds the PDF file for gradual loading in the browser, which does not bring any advantages for raster processors and only wastes time.
Convert to PDF and Convert from PDF
These two groups of settings set default values when converting other formats to and from PDF. As you probably remember, the Distiller application is used to convert to PDF from PostScript and EPS, which allows you to specify different sets of conversion parameters. Acrobat allows you to reduce unnecessary steps and select one of these sets by default, so you can drop PS / EPS on Acrobat itself and get PDF right away without switching to Distiller. This is done in the menu "Preferences> Convert to PDF> PostScript / EPS"... It's also helpful to go over the bitmap format settings so that when opened in Acrobat they turn into PDFs with predictable compression settings. No settings are offered for office formats, but remember that Acrobat will only be able to convert them to PDF if the original office applications are installed on the system. By the way, if this is the case, then many options for converting to PDF are available in Word, Excel, PowerPoint themselves through the Adobe PDF tab .
And in terms of converting from PDF, we are concerned with two scenarios (although keep in mind that you can configure the default export options for any of the listed formats - it may come in handy). The first is the so-called. refrying- fix fatal crashes in PDF through export to PostScript with re-conversion to PDF. This breaks many of the structures in the original PDF at the expense of their lack of PostScript support, but this simplification usually results in files that fail to be output free of their problems. The PostScript export settings shown in the screenshot are optimal for these tasks. They give compact files due to binary encoding and support for the latest (in every sense) third version of PostScript.
The second scenario is simpler, but it can be very useful. This, in fact, is not about settings, but about the command to export all images from PDF at once in their real size. In the tool "Export PDF" (which just uses our default settings)) in the section "Image" there is a subtle checkbox "Exportall images ":
With it, you can export all embedded raster objects in a specified format and compression in the original resolution in one click.
This is especially useful when you need to edit Illustrator graphics (.pdf or .ai) saved in image linking mode. The absence of linked external files at hand leads to the fact that Illustrator opens a file with empty rectangles in place of the images, but here we remember that if we do not disable the default "Save in PDF compatibility mode" checkbox when saving .ai, then our .ai is This is a regular PDF with a couple of attachments that are important only for Illustrator (and as a result, they can and should be inserted into InDesign or QXP layout instead of intermediate formats like EPS). And this means that a copy of images linked in .ai, albeit of screen quality, is still embedded in the file, and they can be reached with such tools for working with images in Acrobat and exported for linking.
By the way, the same is possible in Photoshop. When you open a PDF, it gives you a choice of a method, and allows you to both render the entire page with the necessary parameters (remember the theme of ghosts from flattening transparency) and open any of the embedded images in the original resolution or all at once:
There is also an option to open a 3D model from a PDF, but it has no direct relation to prepress.
Well, that’s where we put the ellipsis ... We have sorted out the basics of settings for productive and predictable prepress, and in the following articles we will take a close look at the tools for checking, editing and correcting PDFs in Acrobat.
Author: Oleg Sidorenko.
Consultation on Adobe Acrobat solution: Polina Krasikova, business development manager for Adobe Acrobat at Softline, Polina.Krasikova@softline.com.
Adobe Acrobat Softline