Converting PDF to EPS, "stepped" curves result

[David Ford]

Hi,

First off, my apologies for not attaching the file(s) in question. I tried but they are over the Creek Forum size limit and I don't have an image reducing program handy.

I have a potential job to engrave a logo onto cedar for a home builder. The file supplied is in PDF format, created with Adobe, simple B&W, and looks fine, all curves being smooth. To manipulate it with Corel X3 I converted it into an EPS file. Once converted the resulting image shows all curves as having "stepped" edges. The image size is approximately 2"x4" and when I blow it up to the required size of ~6"x12" the "steps" are obvious to the point that they can be seen from 10' away on the sample piece.

Can anyone guide me through a process which will eliminate the "stepped" look on the curves? Any/all assistance is appreciated and, yes, I'm a newb.


Cheers,
Dave

[Dave Sheldrake]

Hi Dave,

It depends if the source file was a vector drawing or a raster drawing?

If you want to mail it over I don't mind doing the conversion for you? (I'll also mail back an explanation of how it was done) curves can be smoothed out using AutoCAD or similar but corel draw isn't a particularly good CAD package to be honest, it does a lot of things reasonably well but almost nothing very well.



best wishes

Dave

[matthew knott]

firstly why convert to eps? Corel should happily open a PDF and allow you to manipulate it, it sounds like your curve resolution has gone wrong during the conversion process, which is odd as EPS should handle curves fine, formats like PLT and DXF often don't support curves as such and convert them to lots of little straight lines. Corel should do an excellent job as will Illustrator as they are both specifically designed for working with vector graphics. Stick a copy of the PDF and the EPS and i will be able to tell you what happend during the conversion.
Cheers

[Dave Sheldrake]

All done, the core of the PDF was a vector already, simply extracted it and saved with AutoCAD to a DXF.

best wishes

Dave

[matthew knott]

You really will get a better (how much is open to debate) with a format that can handle proper curves, if it actually be seen is another story. I did quite a bit of work laser engraving custom laser gobos, these where then used a projector slides and the images was projected onto a massive screen, then you could really see the advantage of using the adobe ai format over dxf, as the dxf will always break any curve into lots of little straight lines. Glad its sorted now anyway

[Dave Sheldrake]

as the dxf will always break any curve into lots of little straight lines.

Yup it will indeed unless you convert lines to curves when vectorising or the original format used curves (if it came from a vector that used curves) Only problem with Illustrator and Corel Draw is the compression algorithms can be a pain and cause all sorts of scale issues.
They also use a non standard algo to generate beziers (splines (yuuuuckkk)) that isn't fully compatible with the Chinese lasers (they can display and cut differently).

Of all the formats DWG would be the best but I doubt many companies will be jumping to pay AutoDesk the licence fee's to use it ;)

best wishes

Dave

[Bill Cunningham]

Don't think of a .pdf as a 'format'.. it's simply a digital envelope that will hold just about anything. Text files, super poor .jpgs, vector files in any original format, and high res bitmaps. Opening a .pdf is like opening Forest Gump's box of chocolates. What you get, is what is there.

[matthew knott]

Don't think of a .pdf as a 'format'.. it's simply a digital envelope that will hold just about anything. Text files, super poor .jpgs, vector files in any original format, and high res bitmaps. Opening a .pdf is like opening Forest Gump's box of chocolates. What you get, is what is there.

Aint that the truth, the number of times Ive been all ready to run a job, opened up the PDF and found its unusable SH*T, normally after Ive told the customer I have everything i need so then i can go back and have to sort it out. To be fair this rarley happens now and most pdf's are good to go as we have 'taught' our customer whats needed. Trying to explain what a vector format is to a non-understander is always an uphill strugle mind you!

[Dave Sheldrake]

Trying to explain what a vector format is to a non-understander is always an uphill struggle mind you!

Amen to that brother!!