Stereo analysis
AnalyzedVerdict
Genuine stereo pair97%
The two photographs contain the viewpoint difference needed to produce genuine depth.
- Depth spread
- 10px
- The range of horizontal difference between the two views. More spread generally means more depth; 0–1 px usually indicates a monoview.
- Match
- 97%
- The share of usable picture detail that can be matched between the left and right views. A higher number means a more reliable comparison.
- Vertical
- 2px
- Vertical drift between matched details. Lower is better; 4 px or more can indicate camera movement, scan skew, or poor alignment.
A large mortar and stacked spherical projectiles fill the foreground of this stereoview. Three wheeled cannon stand along a low stone parapet, with two uniformed soldiers positioned between them. Beyond the guns, open water extends to a wooded shore; overhanging branches frame the right side.
The handwritten verso caption reads “From Fort Mackinac,” identifying the viewpoint as Fort Mackinac on Mackinac Island, Michigan. The men are unnamed, and neither their unit nor the date is recorded. The distant shore is not identified.
The yellow mount carries “NORTHERN MICHIGAN VIEWS.” along both side margins. On the reverse is the imprint of B. D. Jackson, Portrait & Landscape Photographer, 108 Monroe Street, Grand Rapids, Michigan. His advertisement offers portrait work “From Cards to Life Size” and a northern Michigan collection including Mackinac Island, Fort Mackinac, Saint Ignace, Petoskey, Bay View, Harbor Springs, Harbor Point, and Charlevoix. This is a general advertisement, not a numbered checklist; the individual view is identified by the handwritten caption.
A few small brown spots appear in the left image’s sky, with a localized brown stain near the lower reverse. The photographs and mount are otherwise clean and sound.
- Title on card
- From Fort Mackinac (inscribed)
- Medium
- Stereoview
- Subject
- Michigan, Occupational, Outdoor Scene, Yellow Mount
- Dimensions
- 7.02 × 3.98 in (178.2 × 101.0 mm)
- Condition
- A few small brown spots in the left image’s sky and a localized brown stain near the lower reverse; otherwise clean and sound, with no visible breaks or significant losses.
- Provenance
- Printed backmark of B. D. Jackson, 108 Monroe Street, Grand Rapids, Michigan; the reverse states “FOR SALE AT JACKSON’S GALLERY.” No former owner is identified.
- Catalogue no.
- MSV1810
Catalogue details
Location
Fort Mackinac, Mackinac Island, Michigan · Mackinac Island, Michigan, United States
Photographed subject · Exact site · 80% confidence
The place is named in the card's own caption or imprint ("Fort Mackinac, Mackinac Island, Michigan"); coordinates resolved by map geocoder (Fort Mackinac, Mackinac Island); building located via Wikipedia article "Fort Mackinac" (https://en.wikipedia.org/wiki/Fort_Mackinac).
Source: Card caption / imprint (direct)
