Why does my PDF get the error: "Form has no blending color space" ?

[Ford Prefect]

I make a lot of stuff in Illustrator CS5 (from scratch) in CMYK. However in many cases when I run them through PitStop Pro 10's Preflight tool, I get parts of my image flagged as "Form has no blending space." Yes there are live transparencies in the PDF. This does not happen to all my documents that have transparency blends in them.

Basically I would like to know:

1- What this error means. My current understanding says this is referring to the various transparency blend types I use, such as Multiply, Screen, Color Dodge, etc. and these blends are not flagged with CMYK or RGB color spaces. Is this correct?

2- What can trigger this error?

3- What things do I need to look out for when designing in Illusrtator? (Number 2 might already give me the answer, but I'll ask this separately anyways).

I'm a new user to PitStop and really want to learn what this means. Any information on this would be great. Thanks.

 

[curveto]

I make a lot of stuff in Illustrator CS5 (from scratch) in CMYK. However in many cases when I run them through PitStop Pro 10's Preflight tool, I get parts of my image flagged as "Form has no blending space." Yes there are live transparencies in the PDF. This does not happen to all my documents that have transparency blends in them.

Basically I would like to know:

1- What this error means. My current understanding says this is referring to the various transparency blend types I use, such as Multiply, Screen, Color Dodge, etc. and these blends are not flagged with CMYK or RGB color spaces. Is this correct?

2- What can trigger this error?

3- What things do I need to look out for when designing in Illusrtator? (Number 2 might already give me the answer, but I'll ask this separately anyways).

I'm a new user to PitStop and really want to learn what this means. Any information on this would be great. Thanks.

The flattener *always* needs a blending (color)space. Blending colorspaces are *always* a three channel construct. For that matter ALL color transforms occur in a three space (so it's really bad to retain a mental grasp on living life exclusively in cmyk ... 'cause even if one thinks that's what's happening, it isn't).

The error indicates that your document (or Illustrator) is configured such that the flattener is unable to convert some (or all) of the material that is needs to (or from) a suitable blending colorspace from cmyk (technically, some source colorspace).

...missing ICC profile(s)?

 

[the_brain]

Hi, the trigger is the existence of form objects in your resulting pdf file. A form object can be compared with a container holding one or multiple objects. Are you grouping elements in illustrator, or using shadings, drop shadows? That could be a trigger.
What pdf preset are you using to create the pdf files?

You could try to this by using the fix to add a blending color space in the preflight profile in the transparency category.

Bert

 

[Stephen Marsh]

Not sure about PitStop, however there is an Acrobat Pro Preflight fix to remove form data.

Stephen Marsh

 

[the_brain]

Not sure about PitStop, however there is an Acrobat Pro Preflight fix to remove form data.

Stephen Marsh

Stephen,

Pitstop has a similar action as part of the action list, but be careful removing form data especially with print related files. You could unknowingly remove sensitive content. I would do a manual check to see what's part of the form object.

It is true that some form Xobjects have no purpose and can be removed completely.

In this case i would still like to know how the pdf was created out of illustrator in the first place.

Bert

 

[leonardr]

I make a lot of stuff in Illustrator CS5 (from scratch) in CMYK. However in many cases when I run them through PitStop Pro 10's Preflight tool, I get parts of my image flagged as "Form has no blending space."

What profile in PitStop are you using?

A PDF is NOT required to have an explicitly defined blending space, so in the general case, the PitStop error is incorrect. However, perhaps you've chosen a profile where someone has (for unknown reasons) decided that they require such a construct. Since, as noted, that isn't a requirement for PDF or any of the PDF standards (eg. PDF/X), I would simply pick a different profile (or fix that one).

 

[leonardr]

The flattener *always* needs a blending (color)space.

That is true. HOWEVER, since one is not required by the PDF standard (ISO 32000-1:2008) NOR any of the PDF/X standards, there are provisions for how a conforming reader would select one when none is explicitly provided.

Blending colorspaces are *always* a three channel construct.

That is FALSE!

The blending colorspace can be ANY VALID PDF colorspace (except for Separation & DeviceN). You can use Gray or CMYK if you wish.

 

[Ford Prefect]

Thanks for all the responses. This is helping me better understand what is happening. The Illustrator file was made in CMYK colorspace with Illusrtator CS5's default color settings. The areas in question are a rounded corner rectangles that are clipped. I used the path finder tools to remove parts of them. I then placed a vector shape with a black to 0% transparent gradient (to act like a drop shadow). The object underneath the "drop shadow" has an outer glow.

I'm using a custom made profile with the Transparency section being used. The option is "Page contains transparent graphic elements and has no blending color space defined" and flagging this as a warning. Trying to help reduce the potential causes of transparency boxes that render the color underneath different from the rest of the image.

I'm wondering if its flagging these areas if they have overlapping transparency regions. The elements in question have that same characteristic. And now when I edited my AI file, removed one of each, "drop shadow" and then outer glow. The elements without the outer glow now no longer show up under this warning. So it looks like in this files case an outer glow is causing it.

Overall the outer glows never turn out to be much of problem when I print them. Other transparency effects can be. I'll have to do some more testing.

Thanks for all the information, it's pushing me in the right direction. Discussions are always great as they get the brain juices flowing.

 

[curveto]

Is that Black gradient stop you made a spot Cs? If so, go there. Turn that rock over.

(I guess the point I was trying to make is that) the flattener needs to be able to convert everything into a "common" colorspace (basis / working) before it can merge. The alert your hitting is because it can't accomplish that goal.

*** Your changes to fix things will inevitably boil down to (the stack o') colorspace choices (again, be judicious 'cause you may get an alternate / choice made for you) and profiles.

My recollection (apparently as old and flabby as the body that holds the cranial orb that emits it) is that (the blending Cs) used to need to be a three channel description. Alas, for me, it's been a decade ago...

FWIW: I helped with original flattener (may she rest in peace) and watched as that was replaced by a more capable design. I'll hold (my) claim to be the first human being on Earth to create a PostScript file that was larger than its raster image equivalent ... which sort of begged the point.

Pretty soon (now) they'll come to wheel me off to the old folks porch (hopefully to sip wine in the company of those I shared earlier days with).

- JR

 

[leonardr]

(I guess the point I was trying to make is that) the flattener needs to be able to convert everything into a "common" colorspace (basis / working) before it can merge. The alert your hitting is because it can't accomplish that goal.

Just to be pedantic - the Flattener needs to convert everything IN A GIVEN GROUP into the same colorspace before it can merge. There may be a single group for an entire page, or there may be MANY groups - it's up to the authoring tool (and/or the author).

The alert is bogus. The user choose a profile check that makes no sense, since there is ALWAYS a blending colorspace - implicit if not explicit.

*** Your changes to fix things will inevitably boil down to (the stack o') colorspace choices (again, be judicious 'cause you may get an alternate / choice made for you) and profiles.

That, I completely agree with!!

My recollection (apparently as old and flabby as the body that holds the cranial orb that emits it) is that (the blending Cs) used to need to be a three channel description. Alas, for me, it's been a decade ago...

Nope - checked the original specs and it's always worked this way.

There are, however, 4 of the blend modes called "non-separable" which MUST always be done in three channels. But the other 9 work just fine for any space.

 

[Ford Prefect]

Are those "non-separable" blends, Hue, Staturation, Luminosity and Color?

Again thanks to all for this plethora of information.

 

[leonardr]

Are those "non-separable" blends, Hue, Staturation, Luminosity and Color?

Yes, those are the ones!