Printer Scaling Issue - incorrectly prints at 99.5% with Mac-Epson ET8550 printer driver

[daveh82726217]

Photoshop 23.5.4 // MacOS 10.15.7 Catalina // Epson ET8550 driver 12.62

Source: Imported 2D CAD Drawing (saved to A4 PDF in CAD then imported into Photoshop).

In Photoshop, drawings scale as 100% using Photoshop Rulers (ie 10cm = 10cm)

• Printing the imported file directly using the A4 plain paper settings produces a correctly scaled diagram, 100%

A new A4 sheet is created from File/New/International Paper/A4 at the same resolution as imported PDF (300DPI) and then the drawing is cut from the original sheet and pasted into the newA4 sheet. These drawings also measure 100% using Photoshop Rulers.

• However printing the NewA4 sheet using the same plain paper printer settings produces an incorrectly scaled drawing of about 99.5%.

Other information:

In Photoshop I save a copy of NewA4 using File/Save As/Photoshop PDF (NewA4.pdf)

• If we read NewA4.pdf into Adobe Acrobat Reader (2022.003.203.14) and print using the same printer driver and settings we get a correctly scaled drawing, 100%.
• If we read this NewA4.pdf into Photoshop and print it we get an incorrectly scaled drawing, 99.5%.

Going back to Photoshop and using the NewA4.psd drawing we can effectively print to PDF using the printer driver, Save as PDF.

• If we read this file into Acrobate Reader and print it we get an incorrectly scaled drawing again, 99.5%

I tried this with A3. The first Photoshop print produced a correctly scaled drawing. Subsequent prints however are incorrectly scaled as well. Is there something being saved with the file after the first print that affects subsequent prints?

[davescm]

Try holding the spacebar when selecting print. That will reset the print dialogue in Photoshop and any print seetings in the current document

Dave

[daveh82726217]

Thanks Dave but that basically resets the DPI to 72 and makes the drawing 123.75cm x 87.48cm. Which kills any scaling of the drawing work I did.

I have been doing more playing. A lot more playing. I now have Mac Big Sur 11.7.7, PS 25.3.1, Epson 8550 driver 13.05. All print operations have no printer scaling or scale to fit involved.

When I import the original CAD PDF into PS (now PS2024) it comes in at 300dpi 19.72cm x 27.62cm and not at A4 as I expected. However the lengths measure perfectly at 10cm using the Photoshop in app rulers/grids. See attached. Whichever way I print this sheet, direct or via PDF in Acrobat all of the prints measure accurate 10cm and 6 inches. I can save this file as a PSD and replicate all of these print operations.

However I like to have my drawings in standard sizes (A4, A3 etc.) and usually have multiple drawings on the same sheet.

So I created a new A4 sheet at 300dpi (standard PS operation) and then cut and copied part of this drawing into the new A4 sheet. As everything is 300dpi all onscreen measurements using rulers & grids are accurate.

If I print this file directly from photoshop the measured printouts are 9.95cm and 5 31/32 inches. Completely repeatable.

If I SaveAS PhotoshopPDF and print out new file from Acrobat the measured printouts are 10cm & 6 inches. Repeatable.

If I SaveAs PhotoshopPDF and print out from Preview the measured printouts are 10cm & 6 inches. Repeatable.

Same thing happens with A3 printouts.

BUT:

If I crop the image to something smaller than the paper size then the direct printing scale is accurate (like the original imported file).

Seems to me that Adobe&Espon don't agree on something around the paper size or printable area limits.

[davescm]

From your description, your print driver is scaling A4/A3 down to account for the border around the paper edge. When not printing borderless it would need to scale or clip that border. I don't have that particular Epson printer here so cannot check the driver, but I would be looking at the Epson print settings (not the Photoshop settings) at any Border/Borderless/Scale to fit ...etc.
Such options in the driver for my Epson SC-P5000 come under the Printing Preferences > Page Layout tab. Also Borderless expansion/reduction settings are in the Main tab.

Note : Holding down Shift when selecting print does not alter the document metadata (inc PPI) at all. It only resets Photoshops print settings.

Dave