Reading Photographs with Image Filters

Faint redness sits against the natural tone of the skin, superficial pigmentation blends into the color around it, and fine texture flattens under even lighting. Image filters display the same photograph in renderings that each bring one of those qualities forward, on the canvas where the photograph is already open. A filter changes only what is on screen.

Choosing a Filter

Filters are chosen from the Image Filter control, an icon button on the canvas toolbar. It opens a picker with one live preview tile per filter, each rendered from the photograph on the canvas, so the tiles show what every filter does to this image before one is chosen. The selected tile is outlined in blue, and selecting a tile applies that filter and closes the picker.

On a narrow toolbar the control moves into the More Options menu, where the same tiles appear under an Image Filter heading.

What Each Filter Shows

The picker lists the filters in this order:

• Original: the photograph as captured.
• Grayscale: the photograph without color. Read for pigment network and border shape without color distraction.
• Invert: the photograph as a negative. Read for border definition and faint network detail.
• Contrast: detail brought forward in both shaded and brightly lit skin, with the color kept. Read for faint pigmentation, subtle redness, and scarring.
• Erythema: redness mapped from white through pale pink and crimson to maroon for the reddest areas. Read for vascularity and the spread of rosacea.
• Pigmentation: pigment rendered darker, in gray. Read for lentigines and the extent of melasma.
• Detail: fine surface structure strengthened, with color and redness unchanged and no bright outline along strong edges such as the nose or jaw. Read for pores, fine lines, and follicular texture.
• Texture: the surface rendered as relief, in gray. Read for the relief of scars, plaques, and wrinkles.

Illustrative demo with synthetic data. Learn more

Adjusting the Strength

While a filter is active, a pill above the toolbar shows the filter name, a strength slider, a readout, and a Clear filter button marked with an X. The readout runs from 0.5x to 2.0x, with 1.0x as the default; lower values give a gentler rendering and higher values a stronger one.

Strength applies to Contrast, Erythema, Pigmentation, Detail, and Texture. Grayscale and Invert have a single rendering, so their slider is disabled.

Choosing a different filter starts it at 1.0x, and selecting the filter already chosen changes nothing. Clear filter returns the canvas to Original and removes the pill. The canvas can be panned and zoomed while the pill is shown, so the rendering is judged at the magnification where it matters.

Illustrative demo with synthetic data. Learn more

Where Filters Are Available

The Image Filter control is on the toolbar of the image viewer, the split and overlay comparisons, the full body Review and Compare views, and Zone Review, in every canvas mode. A photograph can therefore be annotated, arranged, or marked while it is read under a filter.

Annotations, pins, and lesion markers are never filtered; they keep their own colors over the filtered photograph.

In full body Review and Zone Review, the filter and its strength stay in place while stepping from one image to the next, so a series of poses or zone members is read under one rendering.

Comparing Visits Under One Filter

A canvas holds one filter at one strength, applied to every image on it: every section of a split comparison and every layer of an overlay. All of the images are rendered on one scale, so a shade on one visit reads the same as that shade on the other. A photograph can therefore render differently in a comparison than on its own.

Illustrative demo with synthetic data. Learn more

A difference in lighting, white balance, or exposure between two visits shows under a filter as clearly as a change in the skin. The same light, distance, and white balance at every visit are what make a filtered comparison readable.

Filters and the Record

A filter lives only on the canvas that shows it:

• The stored photograph never changes, and the filter is not saved with the record. Every canvas opens on Original, including a comparison reopened later.
• Filter changes are not steps in the undo history.
• Each device keeps its own filter, so two colleagues reading the same comparison each choose their own view.
• If a photograph on the canvas cannot be filtered, the canvas returns to Original.

Export Options, and Quick Export on comparisons, render the active filter and label the exported image with the filter name; Exporting Images with Custom Export describes the label and how filtered exports are logged. Downloads from the Image Properties drawer and PDF reports always use the unfiltered photographs.

Reading the Erythema, Pigmentation, and Texture Filters

Erythema colors anything redder than most of the skin on the canvas, so lips, blonde hair, freckles, moles, and other brown pigment also render pink to red. On darker skin tones, Erythema separates areas of redness from the surrounding skin less clearly.

Pigmentation also darkens redness and shadow, so the shaded side of a face renders darker than the lit side, and areas of redness darken along with pigment.

Texture shades the photograph as if lit from the upper left, so a raised edge is light on its upper-left side and dark on its lower-right side. Lines running from the upper left to the lower right render faintly, so matching folds on the two sides of a face can read unevenly. Flat marks such as freckles and redness mostly stay flat, though a sharp edge in tone can still render as a ridge.

Related Resources

• Comparing Images in Split and Overlay Views for the comparison workspace where visits are read under one filter
• Annotating Clinical Images for the markup drawn over a filtered photograph
• Exporting Images with Custom Export for filtered exports and their label
• Image Filters for an overview of the filters