GCRflow Cloud · Pay with credits
PDF GCR Conversion
GCR0 to GCR100, by paper standard and ink limit
Professional gray component replacement for prepress and print shops. Choose the GCR strength, from GCR0 to GCR100. Official presets convert to GRACoL 2013 at TAC 320%; custom presets let you pick the paper standard (GRACoL 2013, Fogra 27, Fogra 39 or Fogra 51) and a total ink limit from 260% up to the limit offered for that paper standard (320% for GRACoL 2013 and Fogra 39, 340% for Fogra 27, 300% for Fogra 51).
Pay with credits: charged on the first download; previews, re-downloads and failed conversions are free
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- ColorField 1 — GCR strength from GCR0 to GCR100. Official presets target GRACoL 2013 at TAC 320%; custom presets can also target Fogra 27, Fogra 39 or Fogra 51 with a total ink limit from 260% up to the limit offered for each paper standard (320% for GRACoL 2013 and Fogra 39, 340% for Fogra 27, 300% for Fogra 51), and the output intent follows the profile used. RGB with an embedded ICC profile is converted per object using that profile; untagged RGB defaults to ECI-RGB V1.0 and can be switched to sRGB, Adobe RGB or Display P3 (the same rule applies to PDF and TIFF).
- Full-Stack on Google Cloud — Runs in the browser with processing on Google Cloud. No local installation is required.
- Pay per use — Each file is charged in credits when its result is first downloaded; re-downloads, low-res previews and failed conversions are free. See Pricing for the rules.
Live Preview
- Scene — Deep shadows & saturated color
- Product — Deep blacks & vivid color
- Compare appearance before production
- Neutral gray shifted to K
Kernel Card
ColorField 1 — Verified Operating Range
- GCR strength from GCR0 to GCR100. Official presets: GRACoL 2013 at TAC 320%. Custom presets: GRACoL 2013, Fogra 27, Fogra 39 or Fogra 51, total ink limit 260%–340%, within the limit offered for each paper standard.
- RGB with an embedded ICC profile is converted per object using that profile; untagged RGB defaults to ECI-RGB V1.0 and can be switched to sRGB, Adobe RGB or Display P3 (the same rule applies to PDF and TIFF). The RGB rendering intent defaults to relative colorimetric with black point compensation and can be set to perceptual.
- With the same kernel build and parameters, repeated bakes are byte-identical. The integrated interpolation path also passed its bit-identical golden checks.
- On the audited synthetic device-space gradients, second-difference continuity was 22–53× smoother than the previous production path. The multiplier depends on the test gradient and sampling density; it is not a universal constant.
- Does not promise to repair banding already rasterized into the source file.
- The audited conversion path introduced no new banding on the test set.
- Measured improvement was observed where gradient breaks came from the prior color-separation path.
Boundary: ColorField 1 is published only for the range above — coated paper standards only (no uncoated or newsprint profiles), and no custom ICC upload.
Availability: live (charged in credits).
How It Works
Four Steps from Upload to Output
- Upload File — Drag & drop or browse to upload your PDF or TIFF files.
- Choose Tier — Choose a GCR strength from GCR0 to GCR100, or a saved preset with its own paper standard and total ink limit.
- Preview Results — Review the separation preview and job status. Low-res previews are free.
- Download Output — Download the processed file. Credits are charged on the first download; re-downloads are free.
What is GCR?
Gray Component Replacement for Professional Printing
Gray Component Replacement (GCR) is a CMYK separation method that replaces part of the gray component shared by Cyan, Magenta, and Yellow with Black (K).
The effect depends on the source colors and the selected strength. The two examples above are illustrations, not a universal ink-saving claim.
GCRflow processes supported PDF color objects without flattening the entire page into one raster image. Complex production files should be previewed and proofed before press use.
Got Questions?
Frequently Asked Questions
Will it change the PDF layout?
The conversion path rewrites color data at object level and does not intentionally change page geometry, fonts, or document structure. Complex files should still be checked before press use.
What is the difference between GCR and UCR?
UCR concentrates gray replacement in neutral shadow areas. GCR extends replacement into a broader part of the CMYK separation. With GCRflow you choose the GCR strength, from GCR0 to GCR100.
What files work best?
Standard packaging and pre-press production PDFs. For complex objects, test with a small batch first.
What is GCR and how does it reduce ink?
GCR replaces part of the gray component shared by C, M, and Y with Black (K). The resulting TAC change depends on the file and selected tier; GCRflow does not claim one universal reduction percentage.
What is TAC (Total Area Coverage)?
TAC is the sum of the four CMYK channel percentages at a point — for example, C60 + M50 + Y40 + K30 = 180%. Official presets use 320% with GRACoL 2013. In a custom preset you choose the limit from 260% up to the highest limit offered for that paper standard (GRACoL 2013 and Fogra 39: 320%, Fogra 51: 300%, Fogra 27: 340%). At 260% the lowest available strength is GCR30 (GCR40 for Fogra 27), so that dark colors stay accurate.
Start your first GCR conversion now
Upload a PDF and see the full workflow in action.
Showcase images were processed with an earlier version of the GCRflow engine; they are illustrations.