PDFx-1a

[ldrain]

ok, i have a question for all you super-pros out there.

i'm putting together a magazine, we send out PDFx-1a's to our printer etc. all the ads that get placed are also x-1a's. the magazine is created in IDCS2 as well as the majority of the in-house ads. now the question:

does the PDFx-1a automatically convert RGB images into CMYK?

my original thought was no. but after preflighting an ad with images that HAD NOT been converted to CMYK, the preflight shows CMYK for all images. no RGB in the preflight, but the original image was RGB. any ideas?

preflight software is EnFocus Pitstop Pro 6.52, acrobat 7.1.0 OS X 10.4.x

[eugenetyson]

PDF X 1a supports only CMYK and spot colours and nothing more.

The colour conversion happens in the Ouput field, of the PDF dialog box, where it will convert the colours in the document to US Web Coated (SWOP)

If you want to change this you should if you know, as I'm in Europe, I use the Euroscale Coated V2.

If you don't want it to convert the colours then you can select no colour conversion. But then you won't have PDF X1a compliant PDF.

Remember that these are PDF standards, selecting these will generate a PDF to that standard. It isn't a magic fix to make a file print ready, but it's a good start.

[ldrain]

thanks eugene-

that makes enough sense for now. :D

ID converts it to comply to the PDFx-1a standard, otherwise it wouldn't be a PDFx-1a. :D and i do want it to convert to US web SWOP

so is there something i am missing that will warn me i have RGB's in the document? or do i have to go through the links palette?

thanks again!

[Lukas Engqvist]

[QUOTE=ldrain;12921
so is there something i am missing that will warn me i have RGB's in the document? or do i have to go through the links palette?
[/QUOTE]

They agreed that the preflight is out dated. Even if the preflight warns for RGB there is no neecessity to go and change all your images to CMYK. Infact it is probably safer to leave them in RGB, as you run less risk of too much colour.
InDesign uses the same conversion image as Photoshop, so you get the exact same result placing and RGB in InDesign and converting to CMYK at export as if you would have opened the image in photoshop and converted it there.
What you should be aware of is that if you use UNTAGGED rgb files (without a profile) then they will use the RGB space defined as document RGB, but you can override even this by assigning a profile in InDesign, hough I would recommend assigning the profile in Photoshop.

Adobe recommends an RGB workflow. (ie RGB for photographs, vector art and illustrations are best in CMYK preserving values).

A bigger problem with a PDFx1a is that it doesn't warn if you have rasterised text (text is best on top), also be ware of words "auto colour" and RGB black, I normally delete Autocolour and replace with black.

PDFx1a also allows spot colours, which is good if you are printing with spot colours but can give all sorts of problems when printing to CMYK and using transparency. Go to the output:separations box and check that you only have CMYK channels, other chanels should only exist if you are using spot colours, from the separations pannel there is a fly-out menu for Ink manager and you can set Convert all "Spot colours to process" (the ink manager is also available from the print and export dialogues) Note that adding art with a spot colour after you have converted spot colours you will have to convert the new colours by repeating this step.

Any of your adds made with a spot colour, even if made as PDFx1a will have problems if they include spotcolour with transparency.

Hope I didn't scare you…*having said what I said these are problems not only for PDFx1a, but the problems that can still exist inspite of PDFx1a.

[eugenetyson]

Yes that option to Convert Spots to Process tripped me up last week, and I thought it was because I was placing InD files and thought it was a problem with that. Where the spot colour changed in the original file, I neglected to select the option in the Ink Manager again to convert all spots to process.

I really would like the option in the ink manage to "Always Convert Spots to Process". That way, if I have to use a spot colour InD file being placed say into a magazine, I can rest assure that I don't have to go to the ink manager and recheck that pesky box every time.

[ldrain]

thanks you two for the great responses-

lukas- just to clarify, Adobe said that the Pitstop preflight is outdated, or just the preflighting process in general? from your explanation it seems as though the latter is true...

i'm still a little wary of the RGB flow. our photographers will usually readjust the CMYK image after converting it from RGB. they like to have that control and ability to adjust the grey film that seems to come with CMYK conversion.

i am going to go back and double check my settings for spot colors and such. thanks again for the heads up :D