PDF Tools Glossary

Plain meanings of the print terms you meet in the tools and reports. Each term is explained in one sentence; where the tools do something about it, the entry ends with In the tool and what they do. Terms are grouped by topic, and you can link directly to any heading.

Page sizes and areas

Every page in a PDF has several "areas". In the shared report you can also see their names in the PDF: MediaBox is the page size, CropBox is the visible area, TrimBox is the trim area, BleedBox is the bleed area and ArtBox is the content area.

• Bleed: Artwork that extends past the trim line, so that a slightly shifted cut does not leave a white line at the edge; usually 3 mm. In the tool: A missing bleed is warned about edge by edge. The add-bleed tool builds the margin by mirroring the page's own edge image; it does not invent new pixels.
• Bleed area (BleedBox): The PDF's definition of the size of the page including the bleed. In the tool: A missing bleed area is reported as a finding, and a file with findings cannot be Ready.
• Trim size (TrimBox, trim area, finished size, trim): The real size of the job after cutting. Defined in the PDF as the page's trim area.
• Page size (MediaBox): The full size of the page as defined in the PDF. The trim area and the bleed area are defined inside it.
• Visible area (CropBox): The part of the page shown in a viewer and when printing. In most files it is equal to the page size.
• Content area (ArtBox): The PDF's definition of the area taken up by the page's actual content.
• Safe area: The region inside the trim line where text and images that must not be cut off should stay, even if the cut shifts.
• Spine: The edge of a book where it is bound.
• Binding edge: The edge of the page where it is bound. Next to the binding edge, bleed and gaps are considered separately.

Imposition, signatures and binding

• Imposition: Placing pages on the press sheet so that they come out in the right order once folded. In the tool: Saddle-stitch booklet, signature book, N-up. It does not touch the content of the pages.
• Press sheet: The single large sheet of paper that goes into the press. Imposition places the pages on it.
• Signature (forma): A folded print unit. One sheet, once folded, gives a signature of 4, 8 or 16 pages. A signature here is not a digital signature; the word "signature" in the digital sense is used only for digital signing. In the tool: In a signature book each signature is planned with its own page range.
• Signature book: A book whose pages are printed in signatures and folded, after which the signatures are sewn together and bound.
• N-up: Placing several pages on one sheet in a grid. In the tool: 2-up, 4-up and custom grids.
• Step and repeat: Placing the same design side by side on the sheet again and again; used for jobs such as business cards.
• Cut and stack: A layout where the printed sheets are cut and stacked on top of each other so that the page order comes out right on its own.
• Duplex: Printing on both sides of the paper.
• Work-and-turn: Both sides of a sheet printed from one plate. For the second side the sheet is turned over sideways. In the tool: The duplex ready-made workflows with "work-and-turn" in their name place front and back on one plate this way.
• Work-and-tumble: The same idea as work-and-turn, but the sheet is turned over from the top (head over foot). In the tool: The duplex ready-made workflows with "work-and-tumble" in their name place front and back on one plate this way.
• Booklet: A small book made of several sheets folded one inside the other and fastened in the middle.
• Saddle stitch: Fastening folded sheets with wire staples through the spine.
• Perfect binding: Binding by gluing the pages to the cover at the spine.
• Milling allowance: The margin ground off the spine in perfect binding so that the glue can grip.
• Paper caliper: The thickness of the paper in microns (µm). Creep and the spine calculation depend on this value.
• Paper weight: The weight of the paper per square metre (g/m²).
• Creep: In thick booklets, the inner pages stick out further than the outer ones. In the tool: Can be compensated in imposition, if you choose to.
• Gap (gutter): The space left between pages on the sheet. The gutter cut line is the cut line that runs through the middle of this gap; it does not exist in a zero-gutter layout.
• Waste area: The area of the sheet that is not given to pages and is cut off and thrown away.

Print marks

• Crop marks: Short lines at the page corners that show where to cut. They sit outside the bleed.
• Fold marks: Short marks in the margin that show where the sheet is folded. In the tool: The fold-marked booklet ready-made workflows draw a dashed fold mark in the top and bottom margin. Folded leaflets get none.
• Colour bar (colour strip): A strip of small colour patches printed in the margin of the sheet, used to check the printed colours. In the tool: The colour-bar ready-made workflows add 7 patches (C, M, Y, K and 25, 50, 75 % K) in the bottom margin. This adds process colour to the sheet.
• Registration: The name of a special colour that prints on all colour plates at once. Crop and registration marks are usually printed in this colour so that they show on every plate. In the tool: The shared report lists named colours (spot colour, varnish, registration) with the names written in the PDF.

Colour and ink

• CMYK: The four inks of printing: cyan (C), magenta (M), yellow (Y) and black (K).
• RGB: The red, green and blue colour model of screens. It has to be converted to CMYK for print. In the tool: NowToPrint does not convert RGB to CMYK.
• Lab: A device-independent colour model defined according to human vision.
• DeviceN: A colour space that defines several inks together; it appears in spot colour mixes.
• Spot colour: A named ink printed on its own plate instead of being mixed from C, M, Y and K. Varnish and registration are also named colours. In the tool: The shared report lists named colours with the name written in the PDF and a fallback model. Spot colours alone do not block Ready.
• Separation: A colour set aside for its own plate; spot colours are defined in the PDF in this form.
• Varnish: A coating applied over the print; it is drawn in the PDF as a named colour.
• TAC (total ink coverage): The sum of the C, M, Y and K percentages at a point. If it is too high the ink does not dry and smears; the upper limit depends on the paper and the printing method. In the tool: Where it cannot measure, it says "could not be measured" and does not guess. Preflight measures TAC as a lower bound and compares it with the profile in the Screen against selector (Print baseline 330 %, uncoated 280 %). Ask your print shop for the value. The ready-made workflows have limits by paper (coated 330 %, uncoated 280 %, newsprint 240 %, SC 270 %; the measurement is an upper bound), a shared report can show an ink view per page, and Studio can show it as an ink heat map.
• Total ink limit: The highest total ink (TAC) allowed for a paper. In the tool: The ink-limit ready-made workflows in the workflows page check against a fixed limit per paper, or against a number from 100 to 400 % that you type in.
• Coated / uncoated: Coated paper has a coated surface (gloss or matt); it absorbs little ink and tolerates a higher TAC. Uncoated paper has no coating; it absorbs ink and needs a lower TAC limit.
• Rich black: Black made from a mix of all four inks. Good for large areas; in small text it blurs because of misregistration. In the tool: RGB or multi-ink black text under 8 pt is flagged; the tools do not convert it to K on their own.
• Overprint: Printing an object on top of the colour beneath it instead of knocking that colour out. In the tool: The tools do not change overprint settings; that is the RIP's job.
• White overprint: A white object set to overprint. In print, white prints nothing, so the object disappears and the content beneath it stays visible.
• Trapping: Overlapping colours slightly at their edges so that no gap is left between neighbouring colours if the plates shift a little. In the tool: Trapping is left to the RIP.
• Output intent: A record in the PDF that says which printing condition it was prepared for (for example PSO Coated v3 or GRACoL). In the tool: If it is missing it is reported as an info note. The tools do not add an output intent to your file.
• Printing condition (PSO, FOGRA, GRACoL): A standard that defines how colours are printed for a given paper and printing method.
• ICC profile: A profile file that describes the colours of a device or a printing condition.
• Hairline: A line too thin to print. In the tool: A line thinner than the profile minimum is a finding. The tools do not thicken it on their own; fix it in the program the file was made in.
• Small text (point): The point is the unit of type size (1 point = 1/72 inch). Very small text, especially if printed with several inks, becomes unreadable because of misregistration.

Fonts, images and transparency

• Embedded font: The font being saved inside the PDF. If it is not embedded, another font may take its place in print. In the tool: The tools do not embed fonts.
• Outlining: Storing text as a drawing rather than as a font. In the tool: NowToPrint does not convert fonts to outlines.
• Transparency: An object partly showing what is beneath it. PDF/X-4 allows transparency; older standards do not.
• Flattening: Converting transparency into non-transparent parts. In the tool: Flattening is left to the RIP.
• DPI / PPI: The resolution of an image: the number of dots or pixels per inch. If it is low, the image prints blurry.
• Blank page: A page with nothing printed on it. If it is intentional, it is not a problem.

Standards and late binding

• PDF/X: A family of PDF standards designed for sending files to print. PDF/X-4 allows transparency and ICC colour profiles, and it is what we aim for. When PDF/X-1a or PDF/X-3 is the target in our product, RGB becomes a finding. In the tool: The tools aim to work with PDF/X-4; they do not convert your file to X-4.
• PDF/X-1a: The old, strict PDF/X version that allows neither transparency nor ICC profiles.
• PDF/X-3: The PDF/X version that allows ICC colour profiles but not transparency.
• PDF/X-4: The current PDF/X version that allows transparency and ICC colour profiles.
• GWG (Ghent Workgroup): The working group that publishes industry specifications for preparing files for prepress. Preflight profiles can be chosen according to these specifications.
• Late binding: Making decisions such as colour conversion, flattening and font embedding not early in the file, but at the stage closest to printing (in the RIP). In the tool: These operations are not done in the tools.
• RIP: The software in front of the press that turns the PDF into the dots the machine understands. In the tool: Colour conversion, flattening transparency, embedding fonts and trapping are left to the RIP (Late Binding).
• Document facts: The section in the shared single-file report: page count and size, boxes, bleed, fonts, images, and the PDF/X version and output intent the file declares. In the tool: Informational only; it does not change the result or the Ready status. Information that was not recorded says "not recorded" or "not measured", which does not mean "none".

Preflight and results

• Preflight: Checking a PDF for suitability for print before it is printed.
• Finding: A single problem or note found by preflight; it can be an error, a warning or an info note.
• Ready: The check finished clean and complete, and the source of the measurement was verified. Comes only from desktop or server analysis. In the tool: The check in the browser and the workflow preflight on the server never give Ready. See the guide to reading results. It is not print approval.
• Review: There is an error, a warning or an info note; or the file came out clean but the source of the measurement was not verified. In the tool: Look at the findings. Any job that a person has to look at also lands here.
• Could not be evaluated: The check could not be done on this file. It is neither a pass nor a block. In the tool: See the FAQ for the reasons.
• Could not be measured: A value could not be measured from the file. It is shown hatched in the ink view of the shared report.
• Measured proof: A result that was really measured from the file. A preview is not measured proof.
• Page note: A short text the customer writes for a specific page when pressing Ask for changes on the approval link; if they like, it is pinned to a point on the page and shown with a numbered marker. In the tool: At most 20 notes, each at most 300 characters. A page number typed by hand is not checked against the file's real page count; it is plain text. Notes are shown to the member in the Customer approval status panel and on the Approval links page.

Component, template and workflow

• Component: A single unit of work: preflight, edit pages, impose, route, split, spread, review.
• Template: A saved, named setting of a single component. For example, "A5 saddle-stitch booklet" is an impose template.
• Workflow: A flow made of components and their outputs; it uses the templates of the components. Details: Components, templates and workflows.
• Job ticket: An XJDF file (.xjdf, .xml) that carries job information such as binding, paper and quantity. The rules of the Route component look at this information.