What a page's bare numbers mean
Say which declared colour space a page's one, three and four-number colours are read through, and how its marks are composited.
Summary
A colour written as three numbers means nothing on its own: the same three numbers are one colour on a screen and another on a press. A page can name the colour space its bare numbers are read through — one for the greys, one for the three-number colours, one for the four-number ones — so the same request comes out the same colour wherever it is shown.
Technically
Written at the top level of a request, under
"page_spaces"
page_spaces writes the /DefaultGray, /DefaultRGB and /DefaultCMYK of a page, and the transparency group it is composited in. Each names a colour space the request declared under color_spaces; a name the request never declared is refused. group stands over the group the document states for every page. A page named twice takes the last entry given for it, whole.
Request schema
-
page_spaces— array, optional, empty by default. -
page_spaces[].page— integer ≥ 1, required. The page the entry is for. -
page_spaces[].gray— string, optional. The declared space the page's one-number greys are read through. Absent, a grey is whatever the device makes of it. -
page_spaces[].rgb— string, optional. The declared space its three-number colours are read through. -
page_spaces[].cmyk— string, optional. The declared space its four-number colours are read through. -
page_spaces[].group— object, optional. How the page's marks are composited:space— string, required, the declared space they are combined in;isolatedandknockout— booleans, false by default.
A colour stated through color_spaces on the item itself is read as the item says: what a page settles here is only what a bare number means.
A whole request that draws it
{
"color_spaces": {
"house-rgb": { "type": "icc", "components": 3, "profile": "srgb" }
},
"page_spaces": [
{ "page": 1, "rgb": "house-rgb" }
],
"standard_fonts": [{ "name": "sans", "face": "helvetica" }],
"items": [
{
"type": "text",
"rect": { "llx": 60, "lly": 740, "urx": 535, "ury": 765 },
"content": ["Three numbers, read through a space the request declared"],
"font": "sans",
"font_size": 14
}
]
}Colour and how it is shown
The device the colours are stated for Which plate of a separated sheet a page is Declaring colour beyond red, green and blue A colour sliding into another Opacity and how colours mix A cell repeated to fill a shape The space a page mixes its colours in
Where to go next
Every key of a request, in one page The other forty-one settings of a request