File size has become massive after converting to CMYK, even after converting back to RGB?

[nickw29628051]

I was just toying around with art I illutrated converting to it CMYK and after saving, the file size has become massive and now even converting back to RGB the file is huge. This is problem because I need to send this file to my artist colloborator.

How can I reduce the file size back down again?

[Test Screen Name]

What are the comparative sizes? Use your backup of the RGB file to give us both figures.

[nickw29628051]

Original is 70mb the converted and then converted back to CMYK is 180mb!

But I've just found a work around by converting it to Grayscale and then to RGB to comes back to its original file size but I could only do this because my art luckily is black and white. I will not be touching the color space again!

[PECourtejoie]

Hey!

Photoshop has CYMK abilities as it was heavily used in conjunction with Quark Xpress in the Desktop Publishing era.

With the advent of InDesign that has the same color engine, and can ingest RGB files and convert at export time, (if needed, you can then keep a PDF version in RGB for better color rendition), converting to CYMK is way less necessary.

The recommended workflow is to keep the file in RGB, and preview it in CYMK using Proof Colors (CTRL+Y) but to do it with the same profile, you do need to load it in View>Proof Setup>Custom.

This way, you can still use every filters, keep a sane filesize, and see how it would look.

Another great use of Proof color is to use a Dot grain of 15 or 20% to quickly see the exact values of your drawing, instead of the false conversion one gets with CTRL+U (see: https://twitter.com/bobjinx/status/1156246100866740226?lang=en-GB )

[TheDigitalDog]

Original is 70mb the converted and then converted back to CMYK is 180mb!

By @nickw29628051

That seems a bit high. When I convert a 70MB document to CMYK with dither, it lands in at 95MB. 

As outlined earlier, you don't want to convert to grayscale then RGB etc. 

[Stephen Marsh]

Did you have "use dither" turned on in your colour settings or convert to profile settings when converting from RGB to CMYK?

[NB, colourmanagement]

Whatever you do, never convert to CMYK then back to RGB, colour will be lost and that may include detail in saturated areas. 

I hope this helps
neil barstow, colourmanagement net :: adobe forum volunteer:: co-author: 'getting colour right'
google me "neil barstow colourmanagement" for lots of free articles on colour management