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Photography · head to head

RawTherapee vs Sigil

RawTherapee logo

RawTherapee

Photography

Open source raw developer with selectable demosaicing algorithms and floating point processing

From
Free
Rated
-
Full reviewWebsite
Sigil logo

Sigil

Publishing

Open source EPUB editor for working directly on the file, not generating it

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: RawTherapee there is no catalogue, only a folder browser, so any library management, keywording or search has to happen in a separate application.; Sigil it produces no print output whatever, so any book that needs a paperback interior requires a completely separate tool and a second workflow.
  • They diverge on capability: RawTherapee covers Selectable demosaicing, Sigil covers Direct EPUB editing.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which RawTherapee and Sigil actually diverge.

Attributes where RawTherapee and Sigil differ
AttributeRawTherapeeSigil
PlatformsLinux, Windows, macOSWindows, macOS, Linux
CategoryPhotographyPublishing

Identical on both: starting price (Free), pricing model (Open source, no licence fee), free tier (Yes), user rating (Not yet rated).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in RawTherapee

  • Selectable demosaicing
  • Floating point pipeline
  • Local adjustments
  • Wavelet levels
  • Processing profiles
  • Colour management

Only in Sigil

  • Direct EPUB editing
  • Code and preview views
  • EPUB 2 and EPUB 3
  • Regex across files
  • Validation
  • Python plugins

What people use each for

The jobs each tool is most often brought in to do.

RawTherapee

  • Difficult raw files where the demosaicing algorithm visibly changes the result, such as fine fabric, foliage or architectural detailnot Sigil
  • Archive and restoration work where a free tool with strict colour management is preferable to a subscriptionnot Sigil
  • Photographers who want to understand and control each processing stage rather than accept a vendor renderingnot Sigil
  • Producing a high quality sixteen bit TIFF to hand to GIMP or another editor for compositingnot Sigil

Sigil

  • Fixing an EPUB that a retailer validator has rejected, without re-exporting from the tool that generated itnot RawTherapee
  • Correcting the table of contents, reading order or metadata in a file supplied by a conversion servicenot RawTherapee
  • Preparing a back-catalogue title where the only surviving source is the EPUB itselfnot RawTherapee
  • Applying a consistent stylesheet or a bulk text correction across every chapter of a book at oncenot RawTherapee

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

RawTherapee

  • There is no catalogue, only a folder browser, so any library management, keywording or search has to happen in a separate application.
  • The default rendering is deliberately neutral and looks flat next to the camera JPEG, which means every user has to build their own processing profiles before the tool is pleasant to use.
  • Support for new camera models and for Fujifilm X-Trans sensors arrives later than in commercial converters because it depends on volunteer work and upstream library updates.
  • The interface presents several hundred controls across many tabs with little guidance about which ones interact, and the learning curve is measured in weeks rather than hours.
  • Batch export is slow compared with commercial converters and there is no GPU acceleration, so processing a large wedding shoot ties up the machine for a long time.

Sigil

  • It produces no print output whatever, so any book that needs a paperback interior requires a completely separate tool and a second workflow.
  • Meaningful use requires reading and writing HTML and CSS, which puts it out of reach of most authors who simply want a finished file.
  • There is no cloud storage, sync or collaboration, so the book exists as a file on one machine and version control is whatever you set up yourself.
  • Development depends on a small number of volunteer maintainers, so release timing and platform builds follow their availability rather than a roadmap, and a lapse in maintenance would leave no obvious successor.
  • It provides no distribution, no retailer connection and no Kindle-native output, so it sits in the middle of a workflow that other tools have to complete on both sides.

Pricing, plan by plan

RawTherapee

Free
  • RawTherapeeFree
    • GPL licensed with no seat limit
    • All processing features included
    • Documentation and support through RawPedia and the community forum

Sigil

Free
  • SigilFree
    • GPL licensed with no cost or account required
    • Full functionality with no feature gating
    • Community support through forums and the issue tracker

Which should you pick?

Choose RawTherapee if

  • You need selectable demosaicing.
  • You want to start without paying.
  • You work on Linux, Windows, macOS.
  • You also want floating point pipeline.
RawTherapee review

Choose Sigil if

  • You need direct epub editing.
  • You want to start without paying.
  • You work on Windows, macOS, Linux.
  • You also want code and preview views.
Sigil review

Questions people ask

Is RawTherapee or Sigil better?
Neither clearly leads. RawTherapee starts at Free and Sigil at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, RawTherapee or Sigil?
RawTherapee starts at Free and Sigil at Free.
Does RawTherapee or Sigil run on more platforms?
RawTherapee runs on Linux, Windows, macOS. Sigil runs on Windows, macOS, Linux.
Can I use RawTherapee for free?
Both have a free tier, so you can try either at no cost before committing.
What is RawTherapee best used for?
RawTherapee is most often used for difficult raw files where the demosaicing algorithm visibly changes the result, such as fine fabric, foliage or architectural detail, archive and restoration work where a free tool with strict colour management is preferable to a subscription, photographers who want to understand and control each processing stage rather than accept a vendor rendering, producing a high quality sixteen bit tiff to hand to gimp or another editor for compositing. Of those, difficult raw files where the demosaicing algorithm visibly changes the result, such as fine fabric, foliage or architectural detail and archive and restoration work where a free tool with strict colour management is preferable to a subscription are not what Sigil is typically brought in for.
What can RawTherapee do that Sigil cannot?
RawTherapee covers Selectable demosaicing, Floating point pipeline, Local adjustments, Wavelet levels. Sigil covers Direct EPUB editing, Code and preview views, EPUB 2 and EPUB 3, Regex across files.

Answered from the vendors’ own pages

RawTherapee: Does RawTherapee support Fujifilm X-Trans files?

Yes, but support arrived later than in commercial converters and results on fine detail still trail Capture One and Adobe on some bodies.

Sigil: Can I write my book in Sigil?

You can, but you should not. It is an EPUB editor, not a word processor, and writing long-form prose in it is unpleasant. Write elsewhere, import, then finish in Sigil.

RawTherapee: Can it replace Lightroom entirely?

It replaces the develop side. It does not replace the catalogue, so you will need digiKam, darktable or something similar alongside it.

Sigil: Does it make Kindle files?

Not natively. Produce a valid EPUB in Sigil and let Amazon convert it, or use a separate conversion tool for other Kindle formats.

RawTherapee: Are my edits stored in the raw file?

No. Edits are written to sidecar profile files next to the raw, so originals are untouched and profiles can be copied between images.

Sigil: Is it safe to rely on a volunteer project for commercial work?

The files it produces are standard EPUB, so nothing is locked in. The risk is that maintenance stops, not that your books become unreadable.

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