Rated 2 out of 5 stars

Although I absolutely love the idea I did not found any theme I liked too much and the default ones can screw with functionality on some websites.

You are encouraged to compose your own default theme using the basic HSLA transformations.

UPDATE
> The user informed me that he would like to impose certain text or background colors on input elements.

'Color Transform' and 'Colorific' cannot target elements of a specific type. Your best bet is to add specific CSS rules using e.g. 'Stylish', 'User Style Manager' or 'Color That Site'. Given that input elements normally don't contain background or foreground images, it should be possible to obtain a readable result.

> The user informed me that the lack of contrast in most themes led to e.g. indiscernible rating stars.

Color Transform and Colorific are not meant for contrast enhancement, but mainly for darkening pages in order to reduce eye strain in dark environments. However, Colorific's single-spectrum themes retain quite a lot of contrast, while e.g. a mere brightness inversion in Color Transform retains all contrast.

The deeper reasons for the reduced contrast in most themes of Color Transform and Colorific are the following:
Background colors cannot simply be set because they need to be matched to background images. Images require non-constant transformations in order to retain contrast. These transformations are always narrowing down the range of colors if they are to have a similar effect on both bright and dark pages. It is not possible to determine whether a page is predominantly bright or dark without rendering it, and even after that it is hard to estimate. In addition, it is impossible to determine whether text is shown on top of one or more elements which have a CSS background image. Hence it is safe to set text and background colors directly to values with high contrast only if one also hides all CSS background images. In most cases this is unacceptable, because these images have many uses on modern pages as icons and other art work.

Rated 3 out of 5 stars

Doesn't work globally plus it comes to me as complicated with so many settings. Some might like them, I'm more in for something simple and working for all pages at once instead of manually having to set it up for every single page.

Rated 5 out of 5 stars

This is the best working add-on in that category.
There are cases where I would like to have some hue variations within a page, though. For example this review page, setting the stars in the rating did not show. What annoys me the most is that visited and unvisited links look exactly the same, if there is a solution for that I'd be glad to hear it.

The main reason for the limited contrast in the themes of Color Transform is that this ensures that more or less the same result is achieved on dark and bright pages. Simple transformations such as brightness inversion will retain most contrast, but these do not give you control of the resultant colors (for example, dark pages will become bright).

One of the underlying problems is that almost all modern pages use css 'background-image' styles both for backgrounds behind text and for foreground icons/images (such as stars). A theme may now either limit the background colors to a certain range or it may retain the contrast in background images, but it cannot do both.

However, my add-on Colorific contains several single-spectrum transformations that yield higher contrast but less control of the background color. Also, Colorific gives you freely designable themes, so you may try to find a better solution yourself.

For distinguishable link colors, the best solution is to increase the initial contrast in those colors in the Firefox content options.

Rated 5 out of 5 stars

Nice extension! Simple and work well

Just what I wanted Rated 5 out of 5 stars

Great ! I hate BLACK pages. Is there a way to save my preference for a domain? Thanks for this extension

Great potential, but I would like some additional features. Rated 4 out of 5 stars

All-in-all, I love this addon. For a long time I used Stylish for global page adjustments, but the problem with using a global style sheet setup like that is that not all web pages react the same way. It seems that Color Transform, however, reads the individual page data, including the page's own css, and tweaks it to adjust elements to conform to the color transformations set up in the saved color profile. As a result, it doesn't seem to matter how simple, or messy and complex, a page is, Color Transform can do the job and make the page conform to your desired scheme.

But some limitations to the addon make it so that I cannot quite rate this a 5-star addon...

Firstly, while you can choose one of the built-in color schemes, and modify it to customize it the way you want, you cannot save multiple custom color schemes, you can only save a single one. If you change the scheme and save the new customization, the old one is lost.

Secondly, I really wish that the adjustment increments were more fine-tuned. Even using the fine-tune small-increment settings, changing the Hue, Saturation, or Lightness of the color scheme makes some fairly significant and distinct adjustments. On the one hand, it is important to be able to tell the difference between one adjustment and the next, but on the other hand, I personally can distinguish very fine changes in such values, and would like more precise control. Perhaps in the future the developer can add in a third level of adjustment precision for ultra-fine adjustments?

And lastly, I personally would really like to see a built-in site exclusion list. While it is perfectly possible to turn off the change for a given website by turning off the transformations altogether, I would prefer to have it on almost all of the time, and to simply exclude specific rare sites.

I'd also like to make a feature request (other than hopefully seeing the above issues addressed)... I would love to be able to set a "daytime" color scheme, and a "night time" color scheme, and have the addon automatically switch between them (as an option) based on local system time, with the ability to set what times the addon makes that change. I have no doubt that would require a fair bit of additional coding, but I would love to see that option.

Oh, and I'd like to note that it doesn't seem to work with gmail.

Color Transform in its current form won't function in multi-process Firefox which is to be released in several months. I may choose to drop support for Color Transform in favor of Colorific. If you are capable of building a crowd-funding website for new Firefox add-ons / features, please do so.

question Rated 3 out of 5 stars

color schemes are great but as I can automatically activate the color for each open page?

This review is for a previous version of the add-on (4.7). 

Yes. 1) Firstly, apply one or more color transformations to the active page using the theme or transform buttons.
2) Then press the top-left button in the panel to save the applied transformation.
3) Now click the toolbar button to switch automatic transformation of newly opened pages on and off.
4) Alternatively, double-click the toolbar button to apply the saved transformation manually.

Rated 4 out of 5 stars

Pretty neat. Unfortunately it can freeze the browser for a looong time by clicking a few buttons. Maybe web workers or threads could solve this.

This review is for a previous version of the add-on (4.4). 

Web workers are being used for image data, but cannot be used for traversing the document. I have looked into using native dll's or the GPU, but these provide only a minor improvement. The bottleneck seems to be the DOM interaction (as usual). This might perhaps be solved with a fully native implementation, but newer CSS versions may provide a simpler solution in the future. UPDATE: And of course pages may stall while CT is reloading and transforming several 8000px x 4000px background images which some 'web designer' thought he couldn't do without.

Very useful Rated 5 out of 5 stars

Great add-on considering most sites are blindingly white, just what i was looking for and does what it promises!

But how come you can't place its toolbar button in the middle of a toolbar? it goes back to the right side after restart.

This review is for a previous version of the add-on (4.2). 

Rated 1 out of 5 stars

This is an amazing add-on, but I am rating it 1 out of 5 stars because: it doesn't automatically apply the changes before displaying the webpage making it completely unusable at night (versus the way Stylish forces changes before load, thus stopping websites from flashing white before the color is changed), it really needs a blacklist when a global color scheme is set (I don't want it to show on cert error pages) and it makes page hang while loading a new page more noticeable because it takes longer to load pages. Perhaps you (developer) could make Color Transform save changes to Stylish?

This review is for a previous version of the add-on (4.2). 

The flashing of new tabs could be remedied by changing the browser element background color, which I have added to the desired features list (please donate to make it likely to happen :). Colorific, one of my other add-ons, has an option to delay the first paint of web content, which usually suffices to prevent flashing of loading web pages (but you might not like that solution). It also has an option to apply color transforms to white-listed domain only (it has no black-list).

As for Stylish: Color Transform and Colorific work with custom transforms, not CSS transforms. This makes it possible to use arbitrary algorithms for color transformation, but makes it impossible to generate user style sheets. I will consider changing my implementation when the new CSS color spec with HSL filters is implemented in Firefox.

Rated 3 out of 5 stars

Сравнив с Colorific 5.4 и Blank Your Monitor + Easy Reading 1.9.7 от dlento предпочел последний.

This review is for a previous version of the add-on (4.1). 

Since BYM simply sets the Firefox color options, it completely wipes out functional differences between text colors and it may lead to unreadable text on top of background images.

Rated 5 out of 5 stars

Finally after searching everywhere I found a way to change the background color in my browser. I had tried everything including other browsers then I found this.

It is great ! Thank you.

This review is for a previous version of the add-on (4.1). 

Color Transform Rated 5 out of 5 stars

-Excelente.Sufro bastante de la vision y me ayuda mucho.
-Pienso segir utilizandolo.
-Muy facil de manejar
-Practicamente todas las funciones me son muy utiles.
-Gracias.

This review is for a previous version of the add-on (4.0). 

Excelent! [A white-list please. :-D] Rated 5 out of 5 stars

I like this add-on a LOT!

To put it simple it's the best add-on to change in a fast way the colors of a webpage which make it an excellent add-on for reading articles and other things.

For me it's already a 5* add-on, but please please include an option for a white-list for use whit the automatic transformation of all pages, make like a automatic transformation of all white-listed pages! Please. :-P

Other small options like a custom amount of something increase/decrease would also be very appreciated. :-)

Anyway, many thanks for you work.

This review is for a previous version of the add-on (4.0). 

Thanks!

A white list is indeed a good idea, but it will need secured local storage, which I still have to look into.

Besides, the button named 'LS' enables you to toggle between small and large steps for the HSL transforms, but I understand that you want more control. An implementation with sliders could work, but I'm also still thinking about an easy way to specify a color transformation using a fully graphical approach.

Rated 5 out of 5 stars

This seems to do a better job than anything else of changing page background and text colors without wiping out other elements of the page. Would be nice if I could specify my own color scheme.

This review is for a previous version of the add-on (4.0). 

Rated 5 out of 5 stars

Colorific brought me here, and this add-on is much better IMHO. I've been searching for a decent dark global theme on userstyles for days, and this add-on is the only one that actually does what I want -it doesn't hide pictures, doesn't remove background images (creating transparency and overlapping text), and is quite customizable.
In the future, I'd like to see a custom "transparency factor", which defines how intense the presets should be, or even better: a presets editor (e.g. make the "Blue on Black" backgrounds darker while keeping the text intact).
Also, I've seen that you've got the auto enable feature planned, but is there any workaround to auto enable it for now?

This review is for a previous version of the add-on (3.2). 

Thanks for letting me know your opinion and wishes. Currently, there is no way to auto-enable Color Transform or Colorific, but I have started to work on this feature. The presets editor is also on my to-do list - it will probably be implemented as a sidebar with sliders for the coefficients of all effects. Transparency options and a faster approach to image effects are also on my list. Please have some patience :)

Rated 3 out of 5 stars

it would be nice if the effects for websites are not stored

This review is for a previous version of the add-on (3.2). 

You probably mean you want to be able to apply the effect automatically. This feature is on my to-do list for both Colorific and Color Transform, but it will probably take one or two months. (I have been asked for this before, but I first improved the speed of the color transformation.)