more PCB PNP scaling questions

[choklitlove]

i know there's a lot about this, but unfortunately the majority of it is still hazy to me.

(A) when i make a picture of a PCB image, from say DIY layout creator, if i scale it to the right DPI for me (200) and upload for someone else on the web, will it be the same size for them when they print it?

(B) if the answer to (A) is no, how would i achieve that?

(C) what picture format would be best?  jpegs and bitmaps end up too large (file size), gifs lose too much info.  pngs have been looking good and aren't too large, any problem with them concerning browser support or anything?

(D) i know that GGG and tonepad use a lot of PDFs.  they can accomplish good looking layouts and flawless scale.  how do they make PDFs and how do they make them scale correctly for anyone printing straight from the layout?


right now i'm mainly using the gimp, but sometimes i use photoshop and mspaint.  i'm open to others, also.  thanks very much!

[markm]

I've been adding the dimensions to my PNP transfers in the gallery as a guide for people.
Don't if it's helpful or not but, mainly it's because I know of no other feasible way at this point 
I'd like to know myself if there's a better way myself 

[RedHouse]

...but sometimes i use photoshop

C'mon now, if you are using Photoshop you really shouldn't need to be asking this question! 

In the Windows version....

• create your artwork, actual size
• crop the board to the dimensions it needs to be,
• from the "Image" menu select  the "Canvas Size" menu item,

input the size paper you want to print on, then when you save the document select "Save As" and drop down the "Format" box and choose "Photoshop PDF" ....there you have it.

To doublecheck your working size before you save it as a PDF you can select "Print With Preview" and in the dialog box in the "Scaled Print Size" you should select "100%" then print the item and check your pad spacing on the printout for a IC pad space of the usual .1" center.

[choklitlove]

thanks, but i don't currently have my computer.  it's the one with photoshop.  i haven't had it for like 3 weeks.  i've never tried to save as a pdf before when i had it.

[markm]

C'mon now, if you are using Photoshop you really shouldn't need to be asking this question! 

Wait a minute.....
Can I upload a Photoshop PDF file to the gallery here.....I didn't think I could 

[RedHouse]

C'mon now, if you are using Photoshop you really shouldn't need to be asking this question! 

Wait a minute.....
Can I upload a Photoshop PDF file to the gallery here.....I didn't think I could 

I was being sarcastic, sorry if I missed the mark, Mark 

Anyway the key with Photoshop is to create/scale/crop the artwork to it's final size (say 2" x 4" board) then apply a paper size to the image (enlarge the "canvas" to the paper size like 8.5x11" for US and A4 for UK) then print/save/whatever the image which is now the size of a piece of paperwhile the PCB is still 1:1 on the paper, get it?

As far as saving as a PDF, the Photoshop PDF isn't a real vector graphic PDF but will print from Acrobat Reader just fine (which is what most folks have) if you want to create a real vector graphic PDF you will need "Adobe Acrobat" or one of the many inexpensive PDF conversion (printer drivers) available.

I meant to imply that Photoshop just plain rocks when it comes to translating screen art to printable art, it's what it was invented for.
(amoungst other things, hee hee) do yourself a favor if you have PS and don't know how to use it, certainly go get a book or two and walk through the lessons, you'll be glad you did.

[choklitlove]

Wait a minute.....
Can I upload a Photoshop PDF file to the gallery here.....I didn't think I could 

i don't think so.  part of the reason i'd like to find a way to accomplish this with picture files.

[RedHouse]

Wait a minute.....
Can I upload a Photoshop PDF file to the gallery here.....I didn't think I could 

i don't think so.  part of the reason i'd like to find a way to accomplish this with picture files.

And there'in lies the rub, with picture files the print'ee is at the mercy of the picture format.

Bottom line is this: when you print a picture DPI is the factor to sizing the pic, when you do artwork on your computer screen in your drawing program resoution (pixels) is the factor to sizing the pic, and this is why folks have trouble when printing existing artwork.

GIF has a standard of 96dpi (which is crap) and is why when you save as GIF and people print it, it prints small and looses much definition when you scale it back to size....not what we want.

JPG on the other hand can save and hold DPI info and can default to the size of your actual layout art BUT you have to insist on it, what I mean is programs like say Paint Shop Pro have a "settings" dialog box where you set your default DPI for JPG pictures save by you, trouble is it doesn't change along with you and your latest project (which may not be the same DPI) will get defaulted-to what you told it to in the properties dialog box ....better, but still not exactly what we want.

Photoshop, Illustrator, Freehand, Aldus Photostyler and many others turn a pic into a format that saves the pic resoution info you were working at, with a target DPI info you were working toward, and often with JPG at a target compression level (file size) you were striving for. When another person gets this file it prints out exactly the size you intended.

Acrobat PDF files store both resoultion and printing DPI information and is why the PDF is most used to pass around a file that everyone can print precisely the intended size (and why you un-check the "fit to page" option). The only downside of Acrobat is that it tries to compress your picture data so if you are not carefull you can loose crisp edges on PCB traces (RG's Neovibe PDF for instance).

In making a PDF "Portable Document Format" file Acrobat and most other PDF programs usually try to compress it down some to make the file size smaller. A circuit board PDF with some decent 300-DPI artwork (which will etche crisp) can usually end up around 700kb-2mb or better which is less than portable and bums everyone out because they want smaller files, but with better resolution.
(smaller files with better resolution can only really be achieved through a vector graphic program saved to PDF) 

The only way to get the right size otherwise is to print a GIF and tell the program to print it at a certain size, this can be a real hassle, be difficult and can lead a person to doing many trial-n-error printings, while checking each to see if it's the right pad spacing etc.

PDF's are great for this, Photoshop is great for this, GIF/JPG are not so great for this.

Hope this verbiage helps, if not, oh well I needed some typing practice.

[choklitlove]

thanks for the reply.  i do know how to use photoshop pretty well.  for my needs however, i've never needed to deal with scaling like this.  i've also never needed to deal with pdfs in any way.  i've read 2 books, but those parts were very hard to "compute" when i wasn't applying them to something i was using.  thanks again.

[markm]

RedHouse,
Thanks for the info.
I think I'll mess around with this and try out your suggestions.
Thanks again!! 

[RedHouse]

...however, i've never needed to deal with scaling like this.  i've also never needed to deal with pdfs in any way...

Yeah, comming to grips with DPI size -vs- screen size is a headache but once you get a handle on it (in Photoshop) you'll never have any trouble again.

...I think I'll mess around with this...

I wasn't aware the gallery would not take PDF's (I've haven't submitted anything to the gallery) is this by design?

[markm]

...I think I'll mess around with this...

I wasn't aware the gallery would not take PDF's (I've haven't submitted anything to the gallery) is this by design?

Not sure myself.
I've always just uploaded GIFs. 

[Kholinar]

btw... this program allows you to create a PDF from any windows program.  I don't always use it in text documents as it's not always dead on for formating, but for graphics... works great.

http://sourceforge.net/projects/pdfcreator/

[slacker]

If you're using the gimp you can specify the size of the image in millimetres instead of pixels. So you can scale your image to the exact size you want it be and then save it.
Then if you use the gimp to print it you can select print actual size and it will come out the right size. The good thing about this is that it doesn't matter what DPI you print it at it will still be the same size.
Like markm said if you're using images rather than PDFs the easiest thing to do is write the image size on the layout. Then anyone with a decent graphics package can easily scale it to size.

[rockgardenlove]

So uh...what DPI is "100% scale"?

[RedHouse]

...you can specify the size of the image in millimetres instead of pixels...you can scale your image to the exact size you want ...it will come out the right size...it doesn't matter what DPI you print it at it will still be the same size....

Well that works too, it just avoids the whole issue of relating DPI to an physical paper, but if this works for ya, and is understandable then go with it and make PCB's in peace.

If you need to know more, pursue the DPI -vs- Screen Resolution thing I mentioned above, once you realise the relationship, you will never have any sizing trouble again.